Less than or Less then: Which Is Correct?

Updated 2026-10-12 · Which One Is Correct editorial team

Quick answer: When writing comparisons, less than is the grammatically correct choice for your text. Than acts as a conjunction to compare quantities, whereas then belongs exclusively to discussions about time or sequence. Using less then is a frequent mistake that can undermine the clarity of your writing. Always select the word that matches the specific role within your sentence.

The Short Answer

Less than is the correct form for making comparisons of quantity or degree. Choosing this option ensures your writing follows standard English grammar rules without confusion.

People often mix these words up because they sound exactly the same. This confusion usually stems from their similar spelling, even though their meanings and functions in a sentence are completely different.

Side-by-Side Comparison

Form	Status	Use it when
Less than	Correct	Comparing amounts or numbers
Less then	Incorrect	Never use for comparison
Than	Correct	Introducing a comparison
Then	Correct	Referring to time or order

Correct Example Sentences

The price of the jacket is less than the shirt.
Her score on the test was less than his.
This box weighs less than the heavy crate.
We have less than an hour to finish the task.
The distance is less than five miles away.
She earned less than she expected last week.
There is less than a cup of water left.
His height is less than six feet tall.
The cost was less than what we paid.
The value is less than the initial estimate.

Common Mistakes and Fixes

The discount is less then 20 percent off.: The discount is less than 20 percent off.
I need less then five minutes to arrive.: I need less than five minutes to arrive.
This bag costs less then that one.: This bag costs less than that one.
There are less then ten items in stock.: There are less than ten items in stock.
The fee is less then the original price.: The fee is less than the original price.
We spent less then we thought.: We spent less than we thought.

A Quick Test You Can Use

To determine the right word, check if the sentence is comparing quantities or discussing a timeline. If you are comparing amounts, sizes, or numbers, you must choose less than. If you are describing when something happens or the order of events, you should use then instead.

Related Word Pairs

Then/Than: Use than for comparisons and then for time.
Their/There/Theyre: Use their for possession, there for location, and theyre for they are.
Its/It is: Use its for possession and it is when writing the full phrase.
Its/It s: Write its as one word for possession and it s only if you mean it is.
Accept/Accepted: Use accept as the verb and accepted as the past tense or adjective.

Frequently Asked Questions

Can I ever use less then in a sentence?

No, using less then is always incorrect when making a comparison. The word then is reserved for indicating time or sequence, so mixing it with less creates a grammatical error that should be avoided.

Why do people keep making this mistake?

Many writers confuse these words because they sound identical and look very similar. This homophone error is so common that some style guides suggest avoiding the phrase less than entirely to prevent confusion.

What is the difference between than and then?

Than is used specifically to introduce a comparison between two items or values. Then is used to talk about time, sequence, or order, making it the wrong choice for comparing quantities.

Is there a trick to remember which one to use?

Think of the word for time, which is then, and you know when to use it. If you are comparing numbers or amounts, think of the word than, ensuring you choose the correct form for less.