“May” and “shall” are both modal verbs, but they do not normally communicate the same idea.
In modern US English, may is commonly used for permission and possibility. Shall has a narrower everyday role. It can appear in formal questions, formal statements, rules, and legal language, while ordinary future statements usually use other wording.
The key is to look at what the sentence is trying to express. If you are giving someone permission or saying something is possible, “may” is often the natural choice. If you are using a formal command, rule, or a question such as “Shall we begin?”, “shall” may fit.
Quick Answer
May is usually correct when you mean permission or possibility.
- You may leave early.
- We may arrive late.
- May I ask a question?
Shall is mainly used in modern US English in formal language, formal instructions, legal or regulatory writing, and certain questions or suggestions.
- Shall we begin?
- The applicant shall provide the required information.
So, they are not interchangeable in ordinary usage.
One important qualification is that formal and legal writing can give “shall” a context-dependent meaning. US legal references generally describe “may” as permissive and “shall” as mandatory, but they also note that interpretation can depend on context.
Why People Confuse Them
Both words are modal verbs. They come before the base form of another verb:
- may attend
- shall attend
Neither takes a third-person -s, and neither is followed by to before the main verb.
The confusion also comes from older patterns of English. “Shall” once had a much larger role in expressing future time, particularly with I and we. Modern American English generally uses will for ordinary future statements instead.
There is another important source of confusion: “shall” has more than one modern function. Compare:
- You may leave. — permission
- You shall leave. — formal command or requirement
- Shall we leave? — suggestion about what to do
The same word therefore can sound very different depending on the sentence structure.
Key Differences At A Glance
| Feature | May | Shall |
|---|---|---|
| Main modern use | Permission or possibility | Formal instruction, obligation, or suggestion |
| Everyday US use | Common | Limited |
| Permission | Yes | Not normally |
| Possibility | Yes | Not normally |
| Formal questions | Yes | Yes, especially “Shall I…?” or “Shall we…?” |
| Legal/formal rules | Often grants authority | Often expresses a duty |
| Ordinary future | Possible in limited contexts, but not the main function | Uncommon in ordinary US English |
A useful way to remember the difference is:
May = allowed or possible.
Shall = formal requirement or a question about what to do.
That shortcut is helpful, but context still matters, especially in formal documents.
Meaning and Usage Difference
May for permission
“May” can give or request permission.
- May I use your phone?
- You may enter the room.
- Employees may work remotely on Fridays.
This use is especially common in formal or polite requests. In everyday American conversation, people also use other forms to ask for permission, but “may” remains standard.
May for possibility
“May” also expresses something that is possible but not certain.
- The package may arrive tomorrow.
- She may join us later.
- This change may improve the results.
Here, “may” has nothing to do with permission.
Shall for formal requirements
“Shall” can express a duty or requirement, particularly in formal, regulatory, or legal language.
- The applicant shall submit the form by Friday.
- Each member shall follow the stated procedure.
US legal and legislative references commonly describe this as the mandatory function of “shall.”
However, legal interpretation is not always mechanical. Courts can consider the context and purpose of a provision, so “shall” should not be treated as an absolutely inflexible word in every legal sentence.
Shall in questions
“Shall” has a separate function in questions, especially with I and we.
- Shall I open the window?
- Shall we start the meeting?
These questions ask about what should happen next, often as an offer, suggestion, or request for direction. Oxford specifically identifies this question use.
Tone, Context, and Formality
In ordinary American conversation, “may” generally sounds natural when expressing permission or possibility.
- May I sit here?
- It may rain tonight.
“Shall” is much more restricted. Ordinary future statements such as I shall call you tomorrow can sound formal or old-fashioned to many US readers and speakers. Modern American English normally favors other future constructions.
Yet “shall” has not disappeared.
It remains familiar in formal questions:
- Shall we begin?
- Shall I send the report?
It also appears in formal rules and legal documents:
- The tenant shall maintain the property.
- The committee shall meet twice each year.
The tone therefore depends heavily on context. “Shall” in Shall we begin? does not carry the same force as “shall” in a formal rule.
Which One Should You Use?
Choose may when the sentence concerns:
- permission
- authorization
- possibility
- a polite formal request
Examples:
- You may use the conference room.
- The delivery may arrive today.
- May I ask one more question?
Use shall when you intentionally need its formal function:
- Shall we continue?
- Shall I reserve the room?
- The contractor shall provide written notice.
For ordinary future statements in US English, “shall” is usually not the natural choice. I will call you tomorrow is much more typical than I shall call you tomorrow.
In legal or regulatory writing, follow the conventions that govern the particular document rather than replacing every occurrence automatically. Different drafting systems treat “shall” somewhat differently.
When One Choice Sounds Wrong
Some substitutions change the meaning.
Wrong choice for permission:
You shall use the side entrance.
This can sound like a formal command or requirement.
If the intended meaning is permission, use:
You may use the side entrance.
Wrong choice for possibility:
The train shall be late.
This does not normally express ordinary uncertainty in modern US English.
For possibility, use:
The train may be late.
Wrong choice for a suggestion:
May we start the meeting?
This is grammatical, but it asks for permission.
If you mean “Is it a good idea for us to start?”, the structure Shall we start the meeting? can express a suggestion.
The important point is that grammatical correctness and intended meaning are not always the same thing.
Common Mistakes (and Quick Fixes)
Mistake 1: Using “shall” for every future statement
I shall send the file tonight.
This is grammatical, but it can sound formal or old-fashioned in modern US English.
More natural:
I will send the file tonight.
Mistake 2: Using “shall” when granting permission
You shall take Friday off.
If the sentence means permission rather than a formal command, write:
You may take Friday off.
Mistake 3: Treating “may” as a requirement
Employees may submit the form by Friday.
This normally gives permission or indicates an option. It does not ordinarily impose a duty.
Mistake 4: Adding “to” after a modal
We shall to review the report.
Correct:
We shall review the report.
The same pattern applies to “may”:
She may attend.
Not:
She may to attend.
Mistake 5: Adding “-s”
He mays attend.
Correct:
He may attend.
Modal verbs keep the same form with different subjects.
Everyday Examples
| Context | Best Choice | Why |
|---|---|---|
| Asking formal permission | May | “May I come in?” asks for permission. |
| Saying something is possible | May | “The store may close early.” expresses possibility. |
| Granting permission | May | “You may leave now.” gives permission. |
| Suggesting an action together | Shall | “Shall we order dinner?” asks about a shared plan. |
| Offering to do something | Shall | “Shall I carry that for you?” makes an offer. |
| Formal rule or duty | Shall | “Members shall follow the procedure.” creates formal mandatory language. |
| Ordinary future statement | Usually neither | Modern US English normally uses a more ordinary future construction. |
Consider these additional examples:
You may use my charger.
This means permission is being given.
The weather may change this evening.
This means a change is possible.
Shall we meet after lunch?
This is a suggestion.
The applicant shall provide proof of identity.
This is formal requirement language.
Shall I close the door?
This is an offer or question about what action to take.
The meaning comes from the construction and context, not simply from the presence of either word.
Dictionary-Style Word Details
Verb
May: A modal verb used to express possibility, permission, and certain formal functions. It is followed by the base form of a verb: may go, may arrive, may ask.
Shall: A modal verb used in several functions, including formal requirements, formal future statements, and questions about what to do. It is followed by the base form: shall remain, shall provide, shall we begin?
Noun
May: “May” can also be a noun when capitalized as the name of the fifth month: May is usually warm here.
Shall: “Shall” is not commonly used as a noun in standard US English. Its principal modern grammatical role is as a modal verb.
Synonyms
May: Depending on meaning, closest plain alternatives include be permitted to for permission and might or could for some expressions of possibility. These are not exact replacements in every sentence.
Shall: In formal requirement contexts, be required to or must can express a similar idea. In suggestion questions, the meaning may be better conveyed by another question structure rather than a direct synonym.
Example Sentences
May:
- You may use the printer.
- The meeting may run late.
- May I ask a quick question?
Shall:
- Shall we review the proposal?
- Shall I call them tomorrow?
- The applicant shall keep the information confidential.
Word History
Both words have long histories in English.
“May” developed from Old English mæg, associated with being able or having power. Its meanings developed to include permission and possibility.
“Shall” comes from Old English sceal, associated with obligation or being bound to do something. Its later history includes uses connected with future time.
The older history helps explain why “shall” can still carry a sense of formal obligation today, although modern usage is more limited.
Phrases Containing
May:
- May I…? — a formal or polite permission request
- You may… — granting permission
- may be… — expressing possibility
- may not… — denying permission or expressing possibility of a negative outcome, depending on context
Shall:
- Shall I…? — asking what action to take or making an offer
- Shall we…? — making a suggestion
- shall remain… — formal requirement language
- shall not… — formal negative requirement or prohibition, depending on context
FAQs
Is “may” always about permission?
No. “May” also commonly expresses possibility. In You may leave now, it gives permission. In It may rain tonight, it expresses possibility. The sentence context tells you which meaning applies, so “may” should not be reduced to permission alone.
Does “shall” always mean something is required?
No. “Shall” can express a formal requirement, but it also appears in questions such as Shall we begin? and Shall I call you? In modern US English, it can also occur in formal or traditional future expressions.
Can “may” and “shall” be used interchangeably?
No. Replacing one with the other can change the meaning. You may enter grants permission, while You shall enter can sound like a command or formal requirement. In legal writing, context can affect interpretation, so wording must be handled carefully.
Is “shall” common in everyday American English?
No, not for ordinary future statements. Modern American English generally uses other future wording instead. “Shall” remains familiar in formal questions, traditional expressions, rules, regulations, and legal documents, where its tone or function differs from casual conversation.
Why do people say “Shall we…”?
“Shall we…” is a question used to suggest an action or ask what the group should do next. Shall we start? proposes starting. It does not normally mean that the speaker is ordering everyone to start immediately.
Is “may” or “shall” better in formal writing?
Neither is automatically better. Choose “may” when you mean permission, authority, or possibility. Use “shall” when the context intentionally calls for its formal function. In legal or regulatory writing, the governing drafting rules and surrounding language matter.
Conclusion
“May” and “shall” are both correct English words, but they serve different purposes.
Use may mainly for permission or possibility:
- You may leave early.
- The package may arrive tomorrow.
Use shall mainly in formal questions, formal requirements, rules, regulations, and certain traditional expressions:
- Shall we begin?
- The applicant shall provide the documents.
For modern US English, do not treat “shall” as the normal replacement for an ordinary future statement. Its everyday use is limited, while “may” remains a practical and common modal verb.
The safest choice is to match the word to the intended meaning: may for permission or possibility; shall when its specific formal function is intended.
