Let’s is a contraction of let us, an imperative phrase that people use to make or respond to suggestions. The apostrophe is there to indicate that some characters have been omitted (in this case, the space and the u).
Let’s go to the movies.
Let’s pretend we’re kangaroos.
Let’s eat breakfast food for dinner.
Lets is a verb that usually means allows or permits.
He lets his dog sit on the couch.
Jacob works hard all week, but on the weekends he lets it all hang out.
The judge lets criminals off easy.
I have a few tricks for figuring out whether to use let’s or lets. The first thing to check is where the word appears in the sentence. Let’s usually starts a sentence, and lets usually comes later, as in the examples above. This is not a foolproof test, though; there are exceptions both ways:
Don’t let’s get ahead of ourselves.
Lets his lawn grow for months without cutting it, does he? That’s not very neighborly.
Another test to try is to plug in let us and see if it works. I like to imagine it in my snobbiest accent:
✓ Let us adjourn for the day.
✓ Let us imagine we could start all over again.
X My roommate just let us the dishes pile up.
You can also try substituting allows [… to]:
✓ Some people handle rejection well, but Sophia allows it to get to her.
✓ Our boss allows us to leave early on most Fridays.
X “Should we get started?” “Yes, allows to.”
Whenever you are unsure of whether to use let’s or lets, try these tests, and you’ll probably quickly find the correct spelling.
Knowing when to throw in an apostrophe and when to leave it out is hard for many people, and I’ll address the broader issue and other examples in future blogs.