Bloque I. Article III.
The Spanish succession system, regulated by the Royal Decree of July 24, 1889, publishing the Civil Code, establishes a tripartite structure for the distribution of inheritances which balances family protection with testamentary freedom. This division into thirds constitutes one of the fundamental pillars of Spanish inheritance law and represents a sophisticated legal solution that has endured for more than a century.
The system of thirds is not merely a mathematical formula for division but rather responds to a profound legal philosophy seeking to harmonize two seemingly contradictory principles: the autonomy of the testator’s will and the protection of the closest familial bonds. This structure enables the decedent to exercise testamentary freedom while simultaneously respecting the rights the law recognizes for certain heirs by reason of kinship.
What are the Thirds of the Inheritance according to the Spanish Civil Code?
Legal Definition of the System of Thirds
The system of thirds mathematically divides the hereditary estate into three equal parts, each with a differentiated legal nature and subject to specific rules of attribution. This division operates on the computable estate, a concept which comprises not only the assets remaining at the time of death but also the donations made inter vivos by the decedent.
The tripartite structure comprises: the third of strict forced share (obligatorily allocated to forced heirs in equal parts), the third of improvement (also reserved for forced heirs but with distributive flexibility), and the third of free disposition (over which the testator retains absolute freedom).
Legal Basis: Articles 806-807 of the Civil Code
Article 806 of the Civil Code establishes the fundamental concept of the forced share, defining it as “the portion of assets which the testator may not dispose of, as such share is reserved by law to certain heirs, called forced heirs.” This definition forms the theoretical foundation of the Spanish forced heirship system and clearly delimits the restrictions on testamentary freedom.
Article 807 complements this regulation by identifying who has the status of forced heirs: “1. Children and descendants with respect to their parents and ascendants. 2. In the absence of the foregoing, parents and ascendants with respect to their children and descendants. 3. The surviving spouse in the manner and measure established by this Code.” This enumeration establishes an order of priority that reflects the gradation of familial bonds deemed most worthy of protection by the legal system.
The Third of Strict Forced Share: The Untouchable Portion
Concept and Legal Nature of the Forced Share
The strict forced share constitutes the core of the Spanish forced heirship system, representing the purest expression of the principle of family protection in inheritance law. It is an institution of mandatory law operating independently of the testator’s will, establishing itself as a binding limitation on private autonomy in inheritance matters.
This heirship portion is characterized by its qualitative and quantitative intangibility, meaning that the testator cannot deprive the forced heirs of it nor impose encumbrances, conditions, or substitutions of any kind, except for those exceptions expressly provided for by law. Article 813 of the Civil Code enshrines this principle of intangibility as a guarantee of forced heirs’ rights.
Calculation of the Strict Forced Share (Articles 806–807)
The calculation of the strict forced share is based on an arithmetic operation performed on the computable estate in accordance with Article 818 of the Civil Code. This provision states: “To fix the forced share, one shall attend to the value of the assets remaining at the time of death of the testator, deducting debts and charges not including those imposed in the will. To the net value of the heirship assets, shall be added the value of collationable donations.”
The calculation formula operates in two successive phases: computation and attribution. Computation consists in determining the computable mass by the ideal aggregation into the estate of all donations made by the decedent during his or her lifetime, both to forced heirs and to third parties. Attribution involves the allocation of the various liberalities to the corresponding thirds according to their nature and beneficiaries.
Forced Heirs and Their Order of Priority
The status of forced heir is acquired ope legis by the concurrence of certain kinship ties with the decedent. The system establishes a hierarchical order that determines both the amount of the forced share and its internal distribution.
Descendants (children, grandchildren, great-grandchildren) constitute the first category of forced heirs and have rights to two-thirds of the inheritance, distributed between strict forced share and improvement. In the absence of descendants, ascendants (parents, grandparents) succeed with rights to half or a third of the estate depending on whether or not they concur with a surviving spouse. The surviving spouse enjoys forced heir rights configured as a usufruct over varying portions of the inheritance depending on the relatives present.
Equal Distribution Among Forced Heirs
The third of strict forced share must be forcibly distributed in equal parts amongst all forced heirs of the same degree, without the testator being permitted to alter this mathematical equality. This rule of equal distribution constitutes one of the cardinal principles of the forced heirship system and reflects the legal concept of equality among familial ties of identical proximity.
However, the required equality is quantitative, not qualitative, so the decedent maintains freedom to allocate specific assets to each forced heir as long as the global value respects mathematical parity. Such qualitative flexibility allows some customization in succession planning without violating the principle of equality.
The Third of Improvement: Flexibility within the Forced Heirship System
Legal Nature of Improvement (Article 823)
The third of improvement is a characteristically Spanish institution introducing an element of flexibility into the rigid forced heirship system, permitting the testator to adjust the distribution among descendants according to criteria of convenience, necessity, or affection. Article 823 of the Civil Code states: “The father or mother may dispose, in improvement, in favor of one or more of their children or descendants, whether natural or adopted, of one of the two thirds intended for the forced share.”
Improvement is a facultative patrimonial attribution operating within the forced heirship framework but with greater testamentary discretion. It constitutes a conditional forced share actualized only if the testator exercises the improvement faculty; otherwise, it is added to the strict forced share to form the long forced share to be distributed equally.
Beneficiaries of the Third of Improvement
The passive entitlement to receive improvement is strictly limited to children and descendants of the decedent, whether by nature or adoption, regardless of whether they are forced heirs of the first degree. This allows the testator to improve grandchildren even if their parents are alive, offering considerable flexibility in transgenerational succession planning.
The subjective breadth of improvement contrasts with the restrictive entitlement of the strict forced share, enabling the benefit of descendants not qualifying as forced heirs due to others of preferential degree. This feature makes improvement a useful tool for dealing with specific family situations that require differentiated treatment.
Differences with the Strict Forced Share
Differences between improvement and strict forced share go beyond mere quantity to include fundamental qualitative features. While the strict forced share is mandatory and equal, improvement is facultative and unequal, enabling the testator to exercise discretion both in its granting and distribution.
Improvement may be designated in a specific asset pursuant to Article 829 of the Civil Code, while the strict forced share must be satisfied proportionally. Moreover, improvement allows beneficiaries who are not first-degree forced heirs, greatly expanding planning possibilities.
Testator’s Faculties in Improvement
The testator enjoys broad discretion in exercising improvement, freely determining both beneficiaries and the amount and modalities of the improvement within legal limits. This faculty includes the possibility to benefit only one descendant, several in unequal proportions, or even to distribute the entire improvement among descendants of further degrees.
Revocability is another essential aspect of improvement, except where granted for valuable consideration or in prenuptial agreements. Revocability reinforces the highly personal nature of testamentary dispositions and permits succession planning to adapt to changing circumstances.
The Third of Free Disposition: Complete Autonomy of the Testator
Concept and Features
The third of free disposition constitutes the sphere of full testamentary autonomy wherein the decedent may exercise his or her freedom to bequeath unconstrained. It represents the concession that the Spanish forced heirship system makes to private autonomy, allowing a significant portion of the estate to be subject exclusively to the testator’s will.
This heirship fraction is marked by the absolute absence of limitations regarding beneficiaries, modes of attribution, conditions or encumbrances that may be imposed. The testator can assign it in favor of any individual or legal entity, create charitable institutions, foundations, or even dispose of it via inter vivos gifts.
Unrestricted Testamentary Freedom
The autonomy characteristic of the third of free disposition allows the testator to fully express his or her will irrespective of familial ties or proximity criteria. This freedom encompasses both the selection of beneficiaries and the modalities of separation, allowing legacies, heir designations, trusts, or any legal device permitted by law.
The flexibility of the free third facilitates estate planning in complex situations, enabling specific objectives such as the protection of dependents, maintaining business operations, establishing charitable works, or simply manifesting personal preferences.
Beneficiaries of the Free Third
Beneficiaries of the third of free disposition may be any individual or legal entity, without limitation derived from kinship. This broad entitlement stands in stark contrast with the restrictions affecting the forced share and improvement, representing the truest form of testamentary liberty.
The possibility of benefiting outsiders enables the testator to acknowledge affective, professional, or philanthropic ties transcending blood relations. This faculty is especially relevant in contemporary society, where traditional family structures coexist with alternative social and affective organizations.
Practical Calculation of the Thirds: The Computation Operation
Computation According to Article 818 of the Civil Code
Computation constitutes a fundamental accounting process for determining the wealth upon which the thirds of the inheritance must be calculated. Article 818 of the Civil Code sets out the precise methodology: “To fix the forced share one must attend to the value of the assets remaining at the time of the testator’s death, deducting debts and charges not including those imposed by will. To the net value of the estate shall be added the value of collationable donations.”
This operation seeks to prevent fraud against forced heirs’ rights which could arise if the decedent made inter vivos transfers of all or a substantial portion of his or her assets, leaving insufficient estate to satisfy forced shares. Computation ensures that any liberalities made during the decedent’s life are virtually integrated into the mass of the estate for forced heirship calculations.
Value of the Computable Estate
The computable estate is determined by the formula Relictum + Donatum, where relictum represents the net estate left (assets minus liabilities) and donatum comprises all donations made by the decedent during lifetime. Such addition is strictly ideal or accounting, not implying physical reintegration of donated assets into the inheritance assets.
The valuation of the computable elements must be made according to their value at the time of death, not the time of donation, as established by the consistent jurisprudence of the Supreme Court. This temporal criterion guarantees computation reflects the true economic reality at the critical moment succession opens.
Inter Vivos Donations and Their Impact
All inter vivos donations are included in the computation regardless of their beneficiaries, thus both those in favor of forced heirs and outsiders. This universal rule protects the integrity of forced shares against all varieties of gratuitous disposition by the decedent.
The Supreme Court has clarified that computation is conceptually distinct from collation, the former being a calculation operation and the latter a mechanism of equalization among forced heirs. The judgment of March 24, 2025 affirms that “in order to calculate the forced share, for the purposes of Art. 818 of the Civil Code, all donations made by the decedent, whether to forced heirs or outsiders, must be computed.”
Deduction of Debts and Charges
Determining the relictum requires prior deduction of all debts and charges encumbering the decedent’s estate at time of death, with the important exception of those imposed by testament. Such exception avoids artificial reduction of the computable estate by testamentary charges potentially diminishing forced heirs’ rights.
Deductible debts include contractual obligations and those deriving from non-contractual liability, tax, or any other nature, provided they originated prior to death. The burden of proof for such debts is on the party seeking to decrease the computable estate.
Practical Examples with Real Numbers
Case 1: Inheritance with Three Children and No Improvement
Situation: Don Antonio dies leaving an estate of €300,000 and three children: María, José, and Carmen. No lifetime donations were made and no improvement faculties exercised.
Calculation:
- Computable estate: €300,000
- Third of strict forced share: €100,000 (33.33%)
- Third of improvement: €100,000 (33.33%)
- Third of free disposition: €100,000 (33.33%)
Since the testator did not exercise the improvement faculty, the two thirds for forced share (€200,000) are distributed equally among the three children: €66,667 each. The third for free disposition (€100,000) is at the testator’s disposal.
Case 2: Inheritance with Improvement in Favor of One Descendant
Situation: Doña Carmen dies leaving an estate of €450,000 and two children: Ana and Pedro. In her will she fully improves Ana with the third of improvement.
Calculation:
- Computable estate: €450,000
- Third of strict forced share: €150,000 (shared equally)
- Ana: €75,000
- Pedro: €75,000
- Third of improvement: €150,000 (entirely to Ana)
- Third of free disposition: €150,000
Final Result:
- Ana receives: €225,000 (50% of the estate)
- Pedro receives: €75,000 (16.67% of the estate)
This distribution demonstrates how improvement can create significant differences among siblings while respecting the forced heirship principle.
Case 3: Computation with Lifetime Donations
Situation: Don Luis died leaving a net estate of €200,000 and two children. During his life he donated €100,000 to a friend.
Computation Calculation:
- Relict estate: €200,000
- Computable donations: €100,000
- Computable estate: €300,000
Division into Thirds:
- Third of strict forced share: €100,000
- Third of improvement: €100,000
- Third of free disposition: €100,000
In this case, despite only €200,000 remaining at death, the donation of €100,000 is ideally computed, raising the calculation base to €300,000. Each child is entitled to €50,000 of strict forced share, but only €200,000 is in the estate, so the donation would be partially inofficious.
Distinctive Features of the Spanish Forced Heirship System
Differences with Other European Systems
The Spanish forced heirship system presents significant differentiating characteristics compared to other European legal systems. In countries such as France, the forced share is variable according to the number of children; in Germany, a cash entitlement is established; the Spanish model maintains a rigid three-part structure with protection in kind.
The flexibility introduced by the improvement third is a Spanish peculiarity with no direct equivalent in other continental systems. This institution allows the rigidity of forced heirs’ protection to be modulated without abandoning family protection, creating a unique equilibrium between testamentary freedom and forced heirs’ rights.
Protection of Forced Heirs
The Spanish system articulates comprehensive protection for forced heirs that exceeds mere quantitative reserve of assets. This protection includes preventive (computation), corrective (reduction of inofficious dispositions), and procedural (action for completion of forced share) mechanisms guaranteeing the practical effectiveness of forced heirs’ rights.
The action of reduction allows forced heirs to challenge testator’s dispositions affecting their rights, establishing a reduction order privileging first outsiders, then excessive improvements, finally donations, by their date, beginning with the most recent.
Limits on Testamentary Freedom
The forced heirship limits constitute the main restriction on testamentary autonomy in Spanish law, significantly conditioning succession planning possibilities. These are not only quantitative but also qualitative, forbidding imposition of encumbrances or conditions on the strict forced share.
Disinheritance is the exceptional mechanism for overcoming these limits, but only upon occurrence of causes specifically listed in Articles 852 to 855 of the Civil Code. Judicial interpretation of such causes is restrictive, reinforcing forced heirs’ protection.
Legal Testamentary Strategies
Optimization of Succession Planning
Succession planning within the Spanish forced heirship system requires a thorough understanding of the possibilities offered by the different inheritance thirds. The strategic combination of improvements, dispositions of the free third, and use of mechanisms such as Article 831 of the Civil Code can optimize wealth transmission.
Article 831 empowers the testator to entrust distribution to the surviving spouse among common descendants, introducing an element of dynamic management adaptable to post-mortem circumstances. This figure is especially useful where minors are involved or family situations advise deferring distribution decisions.
Combined Use of the Three Thirds
Coordinated use of the three thirds allows the design of sophisticated inheritance strategies simultaneously addressing family protection, acknowledgement of special merit among descendants, and satisfaction of extrapatrimonial aims of the testator.
A frequent strategy is to use the improvement third to compensate for inequalities caused by prior inter vivos donations; the free third for charitable aims or to protect specially related non-heirs; and the strict forced share as basic family protection guarantee.
Tax Considerations
The tax implications of succession planning significantly affect testamentary strategies, especially relating to Inheritance and Gift Tax. Use of improvements may be fiscally more efficient than inter vivos donations in certain scenarios, especially where regional reductions apply.
Coordination between civil and tax planning requires consideration of regional allowances, kinship reductions, and the specific fiscal regime of each Autonomous Community, variables which may tip the scale toward certain estate distribution strategies.
Common Disputes and Their Resolution
Challenge of Testamentary Dispositions
The most frequent succession disputes arise from challenges to testamentary dispositions considered harmful to forced heirs’ rights. Such challenges may be grounded in allegations of inofficiousness, omission, or non-compliance with legal testamentary forms.
Case law has established precise criteria for resolution, holding that the burden of proof of impairment of forced share lies with the challenger, who must prove both entitlement and insufficiency of what was received to satisfy it.
Action for Reduction Due to Inofficiousness
The action for reduction is the specific procedural instrument to protect forced heirs’ rights against prejudicial dispositions by the testator. This action is real and directed against the beneficiaries of inofficious dispositions according to the order established in Article 656 of the Civil Code.
Order of reduction privileges dispositions in favor of outsiders over those for heirs, and within each category applies temporal and quantitative criteria to determine reduction priority. This system ensures the reduction affects primarily the liberalities least related to family duties.
Judicial Protection of the Forced Share
Courts perform an essential function in protecting forced heirs’ rights, interpreting disinheritance causes restrictively and applying strict criteria for admitting exceptions to the forced heirship system. Judicial protection ensures practical effectiveness and prevents erosion by excessively broad interpretations.
Judicial oversight also extends to controls over acts of the surviving spouse entrusted under Article 831, allowing rescission of decisions damaging the strict forced shares of common descendants.
Recent Reforms and Prospects for the Future
Evolution of the Forced Heirship System
The Spanish forced heirship system has undergone significant changes in recent decades, especially owing to reforms enacted by Law 8/2021 on the protection of persons with disabilities. This legislation allows the testator to allocate the strict forced share in favor of disabled descendants, introducing an exception to the forced equality principle.
Regional reforms in territories with special civil law have trended towards greater flexibility, reducing forced share amounts or expanding freedom of distribution among forced heirs. These developments influence debate about future reforms to general law.
Modernization Proposals
Proposals for reform of the forced heirship system aim at greater flexibility adapting wealth transfer to contemporary family realities. Common proposals include reducing forced share amounts, converting forced share into a credit right, and enlarging the causes for disinheritance.
Social evolution towards more diverse family structures and increased longevity pose challenges for the traditional forced heirship system, suggesting the need for adaptions which maintain a balance between family protection and testamentary freedom without sacrificing legal certainty.
Conclusion
The Spanish system of inheritance thirds represents a balanced legal solution that has proven effective for over a century, harmonizing sophisticated protection of family bonds with respect for testamentary autonomy. The tripartite division of assets into strict forced share, improvement, and free disposition offers a normative framework which, without renouncing the underlying solidarity principles of forced heirship, introduces sufficient flexibility to adapt to the specific circumstances of each family.
The strict forced share guarantees the basic protection of forced heirs through equal distribution reflecting the essential equality of family ties of the same degree. The improvement third introduces the discretion necessary for dealing with particular situations requiring differentiated treatment, while the third of free disposition preserves a significant scope for testamentary autonomy. This legal architecture demonstrates that apparently contradictory principles can be reconciled through refined legal techniques.
Practical examples analyzed highlight that the system allows for a wide range of inheritance strategies, from the simplest equal distribution to complex plans pursuing multiple familial and non-familial objectives. The computation operation ensures these strategies cannot be used to defraud forced heirs’ rights, preserving system coherence.
Future prospects suggest that the Spanish forced heirship system will continue evolving to adapt to new social and familial realities, but its fundamental structure appears destined to endure due to its capacity to balance essential legal values. The success of any reform will depend on maintaining this equilibrium without sacrificing the legal certainty that characterizes the current system.
Frequently Asked Questions (FAQs)
1. Can a testator leave his entire inheritance to a single person if he has children?
No, this is not permissible under Spanish general law. If the testator has children, they are forced heirs entitled to two thirds of the estate (strict forced share plus improvement). The testator may only freely dispose of the remaining third. At most, he could favor one child with the entire improvement third, but he may never fully deprive the others of their forced share rights.
2. How do lifetime donations affect calculation of the forced share?
All gifts made by the decedent during lifetime are included in calculating the estate on which the thirds are determined, whether made to forced heirs or outsiders. This computation is ideal (not implying physical reintegration) but may result in some donations being considered inofficious and needing reduction if they impair forced shares.
3. What is the difference between the improvement third and the free disposition third?
The improvement third may only be allocated to children and descendants of the decedent, while the free disposition third may benefit any person. Moreover, improvement is a forced share (family protection), while the free third solely reflects the testator’s will. Both allow unequal distribution, but with distinct beneficiaries.
4. Is it possible to renounce the forced share prior to the death of the decedent?
No, prior renunciation of the forced share is prohibited as it is contrary to public order. Forced share rights only arise upon the decedent’s death, and any prior renunciation would be null. However, renunciation is possible after death via legally established procedures.
5. What happens if the testator does not exercise the improvement faculty?
If the testator does not dispose of the improvement third, it is automatically added to the strict forced share third, forming the so-called “long forced share” distributed equally among all forced heirs. In such cases, forced heirs would receive two thirds of the estate in equal shares, leaving only one third for free disposition.
Next article: Block I. Article IV