Chapter II - Of Contracts, Voidable Contracts and Void Agreements
Section 12
Section 12: What is a sound mind for the purposes of contracting
The question is whether the person could understand the contract and form a rational judgment about its effect at the time it was made.
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This article is for general information. Refer to the Indian Contract Act, 1872 official text for the official provisions. If you need professional advice for your situation, contact Bizeneed.
Statutory text
Bare law
A person is said to be of sound mind for the purpose of making a contract, if, at the time when he makes it, he is capable of understanding it and of forming a rational judgment as to its effect upon his interests.
A person who is usually of unsound mind, but occasionally of sound mind, may make a contract when he is of sound mind.
A person who is usually of sound mind, but occasionally of unsound mind, may not make a contract when he is of unsound mind.
Illustration (a): A patient in a lunatic asylum, who is at intervals of sound mind, may contract during those intervals.
Illustration (b): A sane man, who is delirious from fever or who is so drunk that he cannot understand the terms of a contract, or form a rational judgment as to its effect on his interests, cannot contract whilst such delirium or drunkenness lasts.
Introduction
Capacity is tested at the time the person makes the contract: could that person understand it and form a rational judgment about its effect on their interests?
A person’s usual condition is not conclusive because the section expressly recognizes sound and unsound intervals.
Key takeaways
Time of contract
Assess capacity when the agreement was made.
Two abilities
Understanding and rational judgment about the contract’s effect are both named.
Apply the rule
Record the signing or acceptance time and the terms presented.
Separate evidence about that moment from a general diagnosis or later condition.
Illustration
If a person who is usually unwell enters an agreement during a documented lucid interval, Section 12 requires assessment of capacity at that time.
Practical checklist
Do
- Record the time and circumstances of signing.
- Evaluate understanding and rational judgment about the contract at that time.
Avoid
- Do not infer legal capacity solely from a usual medical condition or a later episode.
Frequently asked questions
Is a usual diagnosis enough?
No. Section 12 focuses on capacity at the time of contracting.
Can a usually sound person lack capacity temporarily?
Yes, the section expressly recognizes occasional unsoundness.
Need help applying this provision to your situation?
Contact BizeneedLast updated 10 October 2026