let is (us) know

Small words-let, let's, lets, and let us-change meaning and tone. Pick the right form and your sentence will sound natural; pick the wrong one and readers stumble. Below are tight rules, plenty of real examples you can copy, and a short checklist to fix any sentence that uses let.

Quick answer - Which form to use?

Use "let's" (with apostrophe) for a suggestion that includes the speaker and listener. Use "let" to grant permission or cause an action; "lets" is the third-person singular form. After "let," use an objective pronoun and the bare verb (no "to"). Don't follow "let's" with a pronoun such as "you and I"-it's redundant.

"Let's" = let us (suggestion): "Let's go."
"Let" (base) = allow/permit: "Let her speak."
"Lets" = allows (he/she/it): "She lets students leave early."

Core explanation: how the forms differ

"Let" is a causative verb: it causes or permits someone to act. After let + object, use the bare infinitive: "Let him try," not "Let him to try." The contraction "let's" joins "let" + "us" and acts as an inclusive suggestion. "Lets" adds -s for third-person singular.

Let + object + base verb: Let her explain.
Let's = let us (contraction): Let's start now.
Lets = allows (third person singular): The app lets you save drafts.

Common mistakes and quick fixes

Most errors come from three simple slips: using the wrong pronoun case (I vs. me), omitting or misplacing the apostrophe, and adding an unnecessary "to" after the object. Fixes are usually one or two words.

Wrong: Let's you and I go for a walk.
Right: Let's go for a walk.
Wrong: Let is know if you need help.
Right: Let us know if you need help.
Wrong: The teacher lets students to choose topics.
Right: The teacher lets students choose topics.
Wrong: She let me to try the demo.
Right: She let me try the demo.

Work examples - professional sentences to copy

Use these corrected lines in emails, memos, or chat. Ask: is this a suggestion that includes you and me? If yes, use "let's." If not, decide whether someone is being permitted (use "let/lets").

Work - Wrong: Let's the team know about the new deadline. Work -
Right: Let the team know about the new deadline.
Work - Wrong: Let John and I decide the agenda. Work -
Right: Let John and me decide the agenda.
Work - Wrong: She let's the staff leave early on Fridays. Work -
Right: She lets the staff leave early on Fridays.

School examples - classroom and academic phrases

Formal writing often prefers clearer alternatives, but when you use "let" forms in notes or emails, these options keep grammar correct and tone appropriate.

School - Wrong: Let John and I present our project tomorrow. School -
Right: Let John and me present our project tomorrow.
School - Wrong: The professor lets us to submit late assignments sometimes. School -
Right: The professor lets us submit late assignments sometimes.
School - Wrong: Let us not to underestimate the reading load. School -
Right: Let us not underestimate the reading load.

Try your own sentence

Test the whole sentence in context: that often makes the correct form obvious. If you're unsure, run the sentence through a grammar checker or rewrite to avoid the "let" construction.

Casual examples - how people speak (and how to write it)

Text and chat tolerate casual phrasing, but written messages benefit from correct forms so meaning stays clear.

Casual - Wrong: Lets go to the movies tonight. Casual -
Right: Let's go to the movies tonight.
Casual - Wrong: Let you and I try it first. Casual -
Right: Let's try it first.
Casual - Wrong: Don't let him to drive if he's tired. Casual -
Right: Don't let him drive if he's tired.

Rewrite help: fix your sentence in three steps

1) Is it a suggestion that includes you and me? Use "let's." 2) Is it granting permission? Use "let/lets" + object + bare verb. 3) Use objective pronouns after let (me, him, us) and remove any extra "to."

Rewrite:
Original: "Let's you and I finish this later." → "Let's finish this later."
Rewrite:
Original: "Let is know when you arrive." → "Let us know when you arrive."
Rewrite:
Original: "She let's to go home early on Friday." → "She lets her team go home early on Friday."

Real usage and tone - when to pick "let's" vs "let us" vs "let"

"Let's" is friendly and direct-great for meetings and messages to colleagues you know. "Let us" (written out) sounds more formal or rhetorical. Use "let" (no s) to mean allow or cause; "lets" marks third-person present. Choose the form that matches the tone you want.

Suggestion (informal): "Let's submit the draft."
Formal/rhetorical: "Let us consider the evidence."
Permission/instruction: "Let the client choose the vendor."

Memory trick, punctuation, hyphenation, and spacing

Mnemonic: If you mean "let us," think apostrophe: let's. If you mean allow/permit, keep it plain: let or lets. After let, use objective pronouns (me, him, us) and the bare verb. There is no hyphenation rule for let or let's; the common mechanical errors are missing or misplaced apostrophes and adding "to" after the object.

Apostrophe: let's = let + us. No apostrophe in lets (he allows).
Pronoun case: let him, let her, let me, let us-not "let I."
No "to" after the object: let them go (not let them to go).

FAQ

Is "lets" the same as "let's"?

No. "Lets" (no apostrophe) is the verb form for he/she/it. "Let's" (with apostrophe) contracts "let us" and is used for suggestions.

Which is correct: "Let John and I compare notes" or "Let John and me compare notes"?

Use the objective case: "Let John and me compare notes." After "let," the people named are objects of the verb, so use "me," not "I."

Can I write "let us" instead of "let's" in a friendly email?

Yes. "Let us" written out is slightly more formal or rhetorical; in casual emails "let's" feels more natural.

Should I ever put "to" after "let" (for example "let him to speak")?

No. When "let" takes an object and a verb, the verb is the bare infinitive: "Let him speak," not "let him to speak."

How do I fix a sentence if I'm not sure which form to use?

Ask three quick questions: Is it a suggestion that includes me and you? Use "let's." Is it granting permission? Use "let/lets" + object + bare verb. Are pronouns used after let? Use objective case (me, us). If you still doubt, rewrite using "we should" or "allow" to avoid the issue.

Want to check one sentence right now?

Paste a sentence into a grammar checker or use the widget above to see which form-let, lets, or let's-works best and get a suggested rewrite you can copy.