In short
The second section of the defects chapter opens with a filter that discards many cases: Article 287 says the error that vitiates the will is the excusable one, in view of the qualities of the subject and in consideration of the greater duty to act with prudence and full knowledge of the circumstances. The article does not define excusable beyond those two measuring sticks, and it does not say whose greater duty that is or greater than what. The same article adds two useful things: if the error is common to two or more parties of a bilateral or multilateral act, any of them may challenge its validity; and ignorance about questions of fact has the same effects as error. Then come the cuts. Article 288 says error about the object only makes the act voidable if it affects the identity, substance, quality or quantity of the object. Article 289 does the same for the person, but with two words instead of four: only if it affects their identity or quality. And Article 290 settles in one stroke the most common argument of all: an error of calculation does not give rise to annulment of the juridical act, only to its rectification. A wrong sum is fixed, it does not bring down the contract. Article 291 closes by stretching the whole section toward a case where you did not err at all: what the preceding articles provide applies to error in the declaration of will and to its inexact transmission by a messenger.
What is it?
They are Articles 287 to 291 of the Civil Code of 2020: which error voids a juridical act, which is merely corrected, and what happens when the messenger erred.
Who can do it?
Anyone who signed believing something else about what they were buying, who they were dealing with, or what the document said.
Requirements
- The error that vitiates the will is the excusable one, in view of the subject’s qualities and the greater duty to act prudently.Verified against the official source
- If the error is common to two or more parties of a bilateral or multilateral act, any of them may challenge its validity.Verified against the official source
- Ignorance about questions of fact has the same effects as error.Verified against the official source
- Error about the object only voids if it affects its identity, substance, quality or quantity; error about the person, only its identity or quality.Verified against the official source
- An error of calculation does not give rise to annulment, only to its rectification.Verified against the official source
- All of the above applies to error in the declaration of will and to its inexact transmission by a messenger.Verified against the official source
Documents you need
Cost
Step by step
Step 1: Rule out the calculation error first
Article 290: an error of calculation does not give rise to annulment, only to its rectification.
Step 2: Ask whether it was excusable
Article 287: only excusable error vitiates the will, measured by the subject’s qualities and the duty to act prudently.
Step 3: See what the error fell on
Article 288: on the object it only counts if it affects its identity, substance, quality or quantity.
Step 4: With the person there are only two
Article 289: error about the person only voids if it affects their identity or quality. It does not say substance or quantity.
Step 5: Add Article 286’s filter
Besides fitting here, the defect must have been determinante for the execution. Two filters, not one.
Step 6: If you did not know a fact, it still counts
Article 287: ignorance about questions of fact has the same effects as error.
Step 7: If the error was shared
Same article: if it is common to two or more parties, any of them may challenge validity.
Step 8: And if the messenger got it wrong
Article 291: all the above applies to error in the declaration and its inexact transmission by a messenger.
Where to do it
These five articles describe no procedure before any agency. The Code does not define here what makes an error excusable, nor what identity, substance, quality or quantity are, nor who decides those things. It does not say whose greater duty to act prudently Article 287 mentions, or greater than what. It does not explain how the rectification of Article 290 is sought, from whom, or within what term. It does not say whether the messenger who transmitted badly answers for anything or to whom. And it sets no deadline for the action. None of those gaps is filled here.
How long it takes
What to do if something goes wrong
Almost every fight over error starts badly because the claim is framed as annulment when the Code has already decided otherwise. If what failed was a sum, a percentage, a conversion or any other calculation, Article 290 is blunt: that voids nothing, it is rectified. Asking for the nullity of a whole contract because the total was miscalculated runs against the text. The second stumble is the word excusable. Article 287 does not protect any mistake whatsoever, only the one that holds up when you look at the qualities of whoever made it and at the duty to act with prudence and full knowledge of the circumstances. Written that way, the article demands more of whoever knows more or should have checked more — though it does not say whom it means, and sets no scale, and this guide does not invent one. The third is believing any error about what you bought will do: Article 288 limits it to the identity, substance, quality or quantity of the object, and Article 289 limits error about the person even further, to identity or quality and nothing more. And on top of all that still sits Article 286’s filter: the defect must have been determinante. Two doors, not one. Two situations people miss are worth keeping in mind. One: if both sides made the same mistake, either of them may challenge, not only whoever complains first. Two: if you were clear about what you wanted and whoever carried your word transmitted it badly, Article 291 treats that case as if the error had been yours; what it does not say is whether anything can be claimed from the messenger. MiPRFácil does not represent anyone in court and gives no legal advice.
Common mistakes
- Seeking annulment for an arithmetic error: Article 290 orders it rectified, not voided.
- Believing any mistake will do: Article 287 only protects excusable error.
- Expecting the Code to say what excusable is: it gives two measuring sticks and no definition.
- Alleging error about the object over a minor detail: only identity, substance, quality or quantity count.
- Applying the object’s four words to error about the person: Article 289 only says identity or quality.
- Forgetting you must also pass the filter that the defect was determinante.
- Thinking that if both erred nobody may challenge: Article 287 lets either of them do it.
- Dropping the case because the messenger made the error: Article 291 treats it the same.
Frequently asked questions
Does a calculation error void the contract?
No. Article 290 says an error of calculation does not give rise to annulment, only to its rectification.
Which error about the thing works for voiding?
Article 288 limits it to one affecting the identity, substance, quality or quantity of the object.
If both of us erred, who may challenge?
Article 287 says that if the error is common to two or more parties, any of them may challenge its validity.
The messenger made the error, not me. Does it count?
Article 291 applies the above to error in the declaration of will and to its inexact transmission by a messenger.
Official sources
These are the government pages this guide is based on.
- Poder Judicial de Puerto Rico
Poder Judicial
bvirtualogp.pr.gov
Last verified
September 12, 2026
MiPRFácil is an independent informational website and is not affiliated with, endorsed by, or operated by the Government of Puerto Rico or any government agency.
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