Lady Blanche sings "Come mighty Must, inevitable Shall" from Princess Ida
An instructor in contract drafting once condemned a contract term I had written:

Party B will pay Party A £25,000 by 30 September.

“You haven’t created an obligation,” he told me. “To impose an obligation, use shall, not will.” I protested that, when A sued for the £25,000, B would need a better defence than: “The contract only said I would pay A the money – it didn’t say I had to”. The trainer, a former partner in a City of London law firm, insisted. “A contract needs to say shall, not will.”


Problems with shall

When I came to study plain English, I found that shall was widely condemned. Legal Usage – A Modern Style Guide says shall “reeks of legalese”. The book devotes the next six pages to explaining the various things that, rightly or wrongly, shall might mean in legal writing, in addition to an obligation.

For example, here is a long and wordy sentence from a lease:

If the Landlords shall fail to exercise their right to require the rent payable hereunder to be reviewed within the relevant period prescribed in paragraph 1(1) hereof or in the event that by the relevant date of review the Landlords and the Tenants shall not have reached agreement and the valuer (if appointed) shall not have given his decision provided for in paragraph 2 hereof then the Tenants shall continue to pay rent at the rate of the rent payable before the relevant date of review on each day appointed by this Deed for payment of rent until agreement shall be reached or the said decision shall be made whichever shall first occur.

Of the seven shalls in this sentence, only one imposes an obligation (to continue paying rent at the old rate).

If you change every shall to will, the same is true; only one imposes an obligation.

(Changing shall to will also makes the other six wills sound strange, because nobody ever says until agreement will be reached. That’s how strange the original shalls sound to many non-lawyers.)


Can I rely on shall to create a contract obligation?

No. When you draft a contract you cannot be sure that every use of shall creates an obligation, especially if the context and commercial purpose support another interpretation.

One risk is that you may undermine an obligation drafted with shall by using shall again in another sense, providing fuel for an argument along these lines:

  • Party: Excuse me, Otherparty, you are in breach of clause X.
  • Otherparty: No, clause X says I shall do something, but look at clauses Y and Z, where shall doesn’t impose an obligation. I contend that clause X is only directory, not mandatory. That makes commercial sense, considering the context, because …

Example: shall expressed permission, not obligation


… all lots uncleared within the time aforesaid shall be resold by public or private sale …


In contract terms for a sale by auction, the court held that these words were permissive, not mandatory. Counsel had pointed out that this phrase was sandwiched between two others in which, he said, shall was clearly permissive.


Robinson, Fisher & Harding v Behar [1927] 1 KB 513

Even if you use shall consistently in the contract, shall might still be given one of its other possible meanings.

Example: shall expressed intention, not obligation


… Motorplus Ltd shall refer a quantity of [specified type] claims to PM Law Ltd Solicitors …


The judge decided, and the Court of Appeal confirmed, that this phrase did not require Motorplus to refer any claims to PM Law, mainly because of the context:

  • No required quantity of claims was specified.
  • The previous contract had not required either party to refer or accept any claims.
  • The reason for the new contract was not to introduce a new commitment, but to change other terms to comply with new rules on referral agreements.

PM Law Ltd v Motorplus Ltd [2018] EWCA Civ 1730, paragraphs 10, 13 to 22, 25 to 27


Is will any better for creating contract obligations?

Will has one advantage: it is still common in everyday English, unlike shall. In British books, there are at least seven wills for every shall. In American English, the Oxford English Dictionary tells us “the word shall is now seldom used in any normal context“.

But will and shall are both vulnerable to the interpretations just discussed, because both have other uses besides creating obligations. And it’s arguable that, at least in the third person and in older documents, the literal meaning of will lacks the coercive force of shall.

What do you mean, “in the third person”?


From the 18th century to the 20th, a rule of grammar swapped the meaning of will and shall according to the “person” involved. The rule was never universally observed and has now almost disappeared. The Oxford English dictionary advises today that “the two words are used more or less interchangeably“.


The old rule gave shall and will these meanings:

  • I, we (first person) … will (obligation) … shall (future intention)
  • You, he, she, it, they, the Party (second or third person) … will (future intention) … shall (obligation)

Knowing this old rule helps to explain this scheme of contract drafting, sometimes found in standard terms:

  • We (the supplier) will do xxxxx.
  • You (the customer) shall do xxxxx.


So why do we always say shall in contracts?

Actually, we don’t always use shall, even in long written contracts.

For example, the NEC form of construction contract is widely used and recommended for building projects. It famously uses only one shall and expresses every other obligation as a narrative, like this:

The Contractor decides the date of Completion. The Contractor certifies Completion within one week of Completion.

Or take the Simple Works Contract for Housing in Western Australia, drafted with must:

Obligations of the owner
The owner must …

Obligations of the contractor
The contractor must …

You can even create obligations without verbs, as in this extract from a contract for sale of goods:

Sellers: Messrs. W. J. Alan & Co. Ltd., Nairobi.
Buyers: Messrs. El Nasr Export & Import Co., Dar es Salaam.
Quantity: 250 tons.
Price: Shs. 262/. (two hundred sixty-two) per cwt. of 112 lb. nett f.o.b. Mombasa.
Shipment From Mombasa: During September 1967/October 1967 at sellers’ option …

(You don’t even need words. You can create a binding contract by pictures, gestures, or behaviour. But that doesn’t help choose words for a written contract.)


OK, what about must? Does must impose a contractual obligation?

To create an obligation, I learned, the best word was must. It’s a familiar word expressing obligation. It doesn’t normally express future intention.

Since at least 2010, official guidance for drafting UK legislation has been to prefer must where possible or, failing that, is to: Office of the Parliamentary Counsel Drafting Guidance (2010), section 2.1, paragraphs 17 to 19. Similar guidance from the Federal Aviation Administration in the USA also extends to contracts.

Does drafting with must guarantee that every use of the word creates an obligation every time? Sadly, no. Drafters can still write in the passive voice, creating an obligation without necessarily identifying which party must perform it. Or they may appear to impose an obligation on someone who isn’t a party to the contract, which is impossible in English law. And, since context and commercial purpose can still occasionally outweigh literal meaning, even must could be interpreted as meaning something else. But it’s the best I can suggest.


But shall sounds better in contracts

When I came to teach contract drafting myself, I discovered that most of the lawyers I taught shrank from writing anything so bossy (and unfamiliar) in their contracts as this:

A must pay B £25,000.

I compromised. Draft your contract with must, I said, because then you will be sure to use it only to create obligations. And then, when you are ready, replace every must with shall. You will at least have used shall consistently to create obligations and nothing else.

But think. Who has to use your contract? Does shall work as well for the users as it does for you? Do the users appreciate the familiar language of your contracts, finding it saves them time in review and negotiation and promotes goodwill between the parties? Or is shall (and maybe other writing habits) working against you? As you labour to deliver timely, commercial and watertight contracts, does your work product whisper something along these lines, undermining your client relations and marketing messages?

We are lawyers, you are not. We don’t speak your language. If we understand your needs, we don’t care about them. Live with it.

If that’s the subtext to your contracts, it’s time to think again about must and will.



  • Comment on this post to share your experience of drafting with must, shall and will.
  • Draft with must, even if you change it to shall or will in the final version.
  • Read the book Clarity for Lawyers for more ways to achieve user-friendly contract drafting.
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Picture credit: Thanks to Gilbert & Sullivan Austin for the picture at the top of this blog post, taken from their performance of Come Mighty Must, Inevitable Shall.

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