One of the most debated topics in legal drafting is the question of shall vs must in contracts. Many lawyers were trained to use the word shall in legal documents, but modern drafting experts increasingly recommend using must instead.
For international lawyers working in English, the distinction between shall vs must in contracts can be confusing. Both words seem to express obligation, but they are used differently in modern legal drafting.
Understanding when to use shall and when to use must is important because unclear language can create confusion or disputes in contracts. This article explains the difference between shall vs must in contracts, why the debate exists, and what most modern drafting authorities recommend.
Why the Debate About Shall vs Must Exists
The debate about shall vs must in contracts comes from the history of legal English.
For centuries, lawyers used the word shall to express obligations in contracts and statutes. Many traditional legal documents contain sentences such as:
The buyer shall pay the purchase price within thirty days.
However, modern legal drafting experts have criticized the word shall. They argue that shall is often ambiguous and can have several different meanings.
For example, shall may sometimes mean:
obligation
future action
permission
determination
Because of this ambiguity, some courts have interpreted shall differently depending on the context.
As a result, many lawyers now prefer the word must when drafting obligations in contracts.
The Traditional Use of “Shall” in Contracts
Historically, shall has been the standard word used to create obligations in legal documents. Many contracts and statutes still contain this traditional drafting style.
Example:
The tenant shall maintain the property in good condition.
In this sentence, the word shall creates a legal obligation.
However, the problem with shall is that it can sometimes be interpreted differently depending on context. In ordinary English, shall is rarely used in modern speech. This makes it more difficult for non-native English speakers to understand.
Because of this problem, the debate about shall vs must in contracts has become increasingly important in modern legal drafting.
The Modern Preference for “Must”
Many modern drafting authorities now recommend using must instead of shall to express legal obligations.
Example:
The tenant must maintain the property in good condition.
In this sentence, the obligation is clearer. The word must directly expresses a requirement.
Modern legal drafting guidelines often recommend must because it has a single clear meaning: obligation.
For lawyers writing contracts in international contexts, using must can reduce confusion and improve clarity.
How Courts Interpret “Shall”
One reason the shall vs must in contracts debate continues is that courts sometimes interpret shall differently.
In many cases, courts treat shall as mandatory. However, in other situations courts may interpret shall as discretionary, meaning it gives permission rather than creating an obligation.
Example:
The parties shall attempt to resolve the dispute through negotiation.
In this example, the phrase may be interpreted as a requirement or merely a suggestion.
Because legal disputes often depend on precise wording, ambiguous terms can create risk.
Advantages of Using “Must” in Contract Drafting
Many modern legal drafting experts recommend replacing shall with must for several reasons.
1. Greater clarity
The word must clearly expresses obligation.
Example:
The licensee must pay royalties within 30 days.
This language is easier to understand.
2. Simpler language
Plain English drafting encourages simpler and clearer language. Using must instead of shall aligns with modern drafting practices.
3. Easier for international readers
Many contracts today are used in international business environments. Lawyers, businesspeople, and regulators may all read the contract.
Using must instead of shall makes contracts easier for non-native English speakers to understand.
Situations Where “Shall” Is Still Used
Although modern drafting experts often recommend must, the word shall still appears in many legal documents.
For example:
older contracts
traditional law firm templates
statutes and legislation
In some legal systems, statutes frequently use shall to create mandatory rules.
Because of this, lawyers must still understand how shall is used when interpreting legal documents.
This is another reason why the distinction between shall vs must in contracts remains relevant.
Best Practices for Contract Drafting
When deciding how to address shall vs must in contracts, many lawyers follow several best practices.
Use “must” for obligations
Example:
The supplier must deliver the goods by the delivery date.
Use “may” for permission
Example:
The buyer may terminate this agreement upon written notice.
Avoid unnecessary complexity
Clear and simple language reduces the risk of disputes.
Maintain consistency
If you choose to use must, use it consistently throughout the contract.
Consistency is one of the most important principles of effective legal drafting.
Examples Comparing Shall and Must
To understand the difference between shall vs must in contracts, consider the following examples.
Traditional drafting:
The contractor shall complete the work by July 1.
Modern drafting:
The contractor must complete the work by July 1.
Both sentences express obligation, but the second version is clearer and more consistent with plain English drafting principles.
Practical Advice for International Lawyers
Lawyers who work in international environments often draft contracts for clients from many different legal systems.
When drafting contracts in English, it is helpful to remember several practical guidelines.
First, prioritize clarity over tradition.
Second, use simple language whenever possible.
Third, consider the audience who will read the contract. If the contract will be read by non-native English speakers, clear wording is especially important.
Following these principles helps ensure that the distinction between shall vs must in contracts does not create confusion.
Final Thoughts
The debate about shall vs must in contracts reflects a broader shift in legal drafting toward clearer and simpler language. While traditional legal documents often relied on shall, modern drafting increasingly favors must to express obligations.
For international lawyers working in English, using must can improve clarity and reduce the risk of misunderstanding. At the same time, lawyers should still understand how shall appears in older contracts and legal statutes.
By choosing precise and consistent language, lawyers can create contracts that are easier to read, interpret, and enforce.
Legal English Lexicon
Ambiguous
Language that can be interpreted in more than one way.
Clause
A specific provision or section of a contract.
Contract drafting
The process of writing legal agreements.
Discretionary
Allowing someone to decide whether or not to act.
Enforceable
Legally valid and capable of being enforced by a court.
Obligation
A legal duty to perform a certain action.
Plain English
A style of writing that uses clear and simple language.
Provision
A rule or clause contained in a legal document.
Statute
A law enacted by a legislature.
Interpretation
The process of determining the meaning of legal language.
