Jurisprudence, Interpretation and General Laws · Sources of Law

Custom as a Source of Law: Essentials and Kinds

Updated 11 October 2026 · Fact-checked

Custom is a long-followed rule of conduct that a community treats as binding. It becomes law when courts or the State recognise it. To answer exam questions, define custom, name its kind, test it against the essentials (antiquity, continuity, certainty, reasonableness, compulsory observance, consistency with statute), then conclude on validity.

Understand Custom as a Source of Law

A custom is a habit of conduct that a group of people follows for a long time and feels bound to follow. Nobody passed it as an Act. It grew out of the life of the community. In early societies, custom was the main law. Legislation and precedent came later.

Custom is not law merely because people follow it. It turns into law when a court enforces it or the State accepts it. Salmond's view is that custom is a source of law because it is first practised, then recognised and enforced by the courts. The practice comes first; the legal force comes from recognition.

Customs are of two main kinds. Legal custom has the force of law and courts enforce it directly. It is of two types: local custom, which applies to a place or a family or class of persons (for example, a custom of inheritance in a particular community), and general custom, which applies across the whole country (the common law of England grew from this). Conventional custom is also called usage. It binds parties only because they have agreed to it, expressly or by implication, as in a trade usage. It must be proved and cannot override the express terms of a contract.

A custom must satisfy certain tests before a court recognises it. It must be ancient, continuous, certain, reasonable, observed as compulsory and not against statute or public policy. The person who relies on a custom must prove it. Where a custom has been recognised by courts again and again, later courts take judicial notice of it, and it then merges into precedent.

In India, custom still matters, mainly in personal laws, family and succession matters, and in tribal communities. Modern statutes often say that a custom is saved or is overridden. When a statute and a custom conflict, the statute prevails, unless the statute itself saves the custom.

Key rules to remember

Meaning of custom: Custom = long-continued practice of a community + belief that it is binding + recognition by courts/State; Practice alone is not enough. Binding belief and recognition turn it into law.
Kinds of custom (Salmond): Custom → Legal (local, general) and Conventional (usage); Legal custom operates as law by itself. Conventional custom binds only through agreement of the parties.
Essentials of a valid custom: Antiquity + Continuity + Certainty + Reasonableness + Compulsory observance + Conformity with statute and public policy; Add that the custom must be proved by the person relying on it. Some texts add 'peaceable enjoyment' and 'uniformity'; mention them if you wish.
Custom vs statute: Statute > Custom (unless the statute saves the custom); A custom cannot override an express provision of law.

How to solve Custom as a Source of Law questions

Use this order for any question on custom, whether it asks you to explain, distinguish or apply.

1Define custom in one or two lines. Say it is a practice followed for long and treated as binding.
2State how it becomes law: through recognition by courts or the State. Mention Salmond's approach.
3Name the kinds: legal (local and general) and conventional. Give a one-line example of each.
4List the essentials of a valid custom. Give one short explanation for each, not just the names.
5If the question has facts, test each fact against the essentials one by one.
6If asked to distinguish custom and usage, write at least four points: source of binding force, need for agreement, proof, effect on contract or law.
7End with a clear conclusion: valid or invalid, and why. Mention that statute prevails over custom.

Quickest way: Six-test checklist for custom

When to use it: Use it for a short note or a fact-based question when time is limited.

Write: Old? (antiquity)
Write: Continuous? (no break)
Write: Certain? (clear and definite)
Write: Reasonable? (not unfair or against public policy)
Write: Obligatory? (followed as a duty, not by choice)
Write: Consistent with statute? Then give your verdict in one line.

Common mistakes in Custom as a Source of Law

Treating custom and usage as the same thing.
Both are repeated practices, so the words look alike.
Fix: Remember: legal custom binds as law; usage binds only by agreement of the parties. Write this as your first point of difference.
Saying any habit followed by many people is a valid custom.
Students forget the tests and focus on popularity.
Fix: Always add that the practice must meet the essentials and be proved. Without recognition by courts or the State it is not law.
Listing the essentials as bare words with no explanation.
Students memorise a list to save time.
Fix: Give one line for each essential, for example: antiquity means the practice has existed since long before living memory.
Claiming a custom can override a statute.
Students over-weight the importance of custom in personal law.
Fix: State that a custom must conform to statute. It prevails only where the statute saves it.
Mixing up local and general custom, or placing conventional custom under legal custom.
The classification has two levels and students blur them.
Fix: Draw the tree: Custom splits into Legal and Conventional; Legal splits into Local and General.
Leaving out proof of custom.
Students think a custom is known to the court automatically.
Fix: Add that the person who claims a custom must prove it. Only a long-recognised custom is noticed by courts without fresh proof.

Worked examples

Example 1

Explain custom as a source of law. What are the essentials of a valid custom?

Show the solution

Define: A custom is a rule of conduct that a community has followed for a long time and regards as binding on its members.
Link to law: A custom becomes law when the courts or the State recognise and enforce it. On Salmond's view, practice comes first and legal force follows from recognition.
Kinds: Legal custom (local or general) is enforced as law. Conventional custom, or usage, binds only because the parties have agreed to it.
Essentials: (1) Antiquity: it has existed from a very long time. (2) Continuity: it has been followed without a break. (3) Certainty: its terms are clear and definite. (4) Reasonableness: it is not unfair or against public policy. (5) Compulsory observance: people follow it as a duty, not by choice. (6) Conformity with statute: it does not conflict with an express law.
Proof: The person who relies on the custom must prove that it meets these tests.
Conclusion: Only a custom that satisfies these tests is recognised as law by the courts, and a statute prevails over it unless the statute saves it.

Answer: Custom is a long-followed, binding practice of a community that becomes law on recognition by courts or the State. A valid custom must be ancient, continuous, certain, reasonable, compulsorily observed and consistent with statute.

Example 2

Distinguish between custom and usage. A trade association in a market follows a practice, for the last few months, of allowing a 2% discount on cash payment. Is this a valid legal custom?

Show the solution

Difference 1, source of force: A legal custom binds as law because the courts recognise it. A usage binds only through the express or implied agreement of the parties.
Difference 2, agreement: Legal custom applies whether or not the parties knew of it. Usage applies only if the parties adopted it, or are taken to have adopted it.
Difference 3, effect: Usage cannot override the express terms of a contract. Legal custom has the force of law within its area or class.
Difference 4, proof: Both must be proved, but usage must also be shown to have been accepted by the parties.
Apply to facts: The practice has lasted only a few months. It lacks antiquity and has not been shown to be continuous over a long time.
It is also a commercial practice agreed between traders, so at most it is a conventional custom, that is, usage.
Conclusion: It is not a valid legal custom. It may bind parties as usage if they have agreed to it, expressly or by implication, and if it does not contradict their contract.

Answer: The practice is not a legal custom because it lacks antiquity. At best it is a usage that binds only those parties who have agreed to it and only if it does not conflict with their contract.

Exam tips

Draw a small classification chart (Custom → Legal/Conventional → Local/General) before the explanation. It earns clarity marks.
In a distinguishing question, give at least four points in a clear two-column style, written in lines. Do not stop at two.
Always cite Salmond for the idea that custom gains legal force through recognition, but do not invent case names.
For fact-based questions, take each essential in turn and apply it to the facts, then write a one-line conclusion.
Link custom to the other sources in a line. Statute can override custom, and recognised custom can become precedent.

Practice questions from Sources of Law

Custom as a Source of Law in other exams

The same ground in other exams, if you are preparing for more than one or want another angle on it.

Custom as a Source of Law: frequently asked questions

What is the difference between custom and usage?

A legal custom is a long-followed practice that courts enforce as law. A usage, or conventional custom, binds only because the parties agreed to it, expressly or by implication. Usage cannot override the express terms of a contract.

What are the essentials of a valid custom?

A valid custom must be ancient, continuous, certain, reasonable, observed as compulsory and consistent with statute and public policy. The person who relies on it must prove it. Write one line of explanation for each essential in your answer.

What are the kinds of custom?

Custom is of two kinds: legal and conventional. Legal custom is further divided into local custom, which applies to a place or class of persons, and general custom, which applies across the country. Conventional custom is the same as usage.

How does custom become law according to Salmond?

Salmond treats custom as a source of law because a practice that people follow becomes law when the courts or the State recognise and enforce it. The practice is the material, and recognition gives it legal force.

Can a custom override a statute?

No. A statute prevails over a conflicting custom. A custom survives against a statute only if the statute itself saves it.