Less than is the standard expression used when you compare a smaller amount, number, value, measurement, duration, or degree with another amount or standard.
Less then is not the standard comparative phrase. The problem comes from confusing than, which introduces comparisons, with then, which commonly refers to time, sequence, or what happens next.
For example:
- The repair took less than two hours.
- The jacket costs less than $50.
- The second option was less than ideal.
In each sentence, than connects less to something being compared.
Quick Answer
Use less than when you mean “a smaller amount or degree than.”
- Correct: The package weighs less than five pounds.
- Correct: We finished in less than an hour.
- Correct: The new plan costs less than the old one.
Use then for time, sequence, or a resulting action:
- We ate dinner and then went home.
- Finish the form, then submit it.
So, when the intended meaning is a comparison, less than is the correct choice. Less then should not replace it.
Why People Confuse Them
The mistake is easy to make because than and then look almost identical and can sound similar in everyday speech.
There is also a useful grammatical difference:
- Than introduces a comparison.
- Then commonly shows time, sequence, or consequence.
Consider these two sentences:
The trip took less than three hours.
Here, than introduces the amount used for comparison.
We arrived at the hotel and then checked in.
Here, then shows the order of two actions.
The spelling difference is small, but the grammatical jobs are different.
Pronunciation can add to the confusion. In normal speech, both words may be pronounced with a reduced vowel, especially when they are unstressed. That can make the distinction harder to hear than it is to see in writing.
Key Differences At A Glance
| Feature | Less than | Less then |
|---|---|---|
| Main role | Comparison | Not a standard comparative phrase |
| Meaning | A smaller amount, degree, value, or measurement | Usually a mistaken use of then |
| Grammar | Than introduces comparison | Then normally refers to time or sequence |
| Standard comparative use | Yes | No |
| Example | less than $20 | less then $20 ❌ |
The key is not the word less. The important choice is between than and then.
Meaning and Usage Difference
Less than tells readers that something falls below a stated amount, measurement, degree, value, or standard.
It works naturally with many kinds of comparisons.
Amount
I have less than $20 in my wallet.
The amount is below $20.
Time
The meeting lasted less than forty minutes.
The duration is below forty minutes.
Distance
The hotel is less than a mile from the station.
The distance is below one mile.
Measurement
The package weighs less than five pounds.
The weight is below five pounds.
Degree
The new version is less effective than the previous one.
The sentence compares the degree of effectiveness.
Quality or expectation
The response was less than helpful.
Here, less than expresses a degree that falls short of the quality named afterward.
By contrast, then does not introduce these comparisons. It normally places an event in time or order:
We finished the meeting, then we went to lunch.
The two words therefore cannot be exchanged simply because they sound similar.
Tone, Context, and Formality
Less than is neutral and works across everyday and formal American English.
You can use it in:
- Everyday conversation
- Emails
- School writing
- Workplace communication
- Reports
- Technical writing
- Formal documents
For example:
The update took less than ten minutes.
There is nothing unusually formal about this sentence. It is simply standard English.
The problem with less then is grammatical rather than stylistic. It is not a casual alternative to less than. Writing less then when you mean a comparison can make the sentence look like a word-choice error.
The same distinction applies whether you are writing a text message, a school assignment, or a professional report.
Which One Should You Use?
Choose less than whenever the sentence compares something with an amount, measurement, value, degree, or limit.
Use:
- less than $100
- less than an hour
- less than five miles
- less than expected
- less than ideal
- less than before
Choose then when you are talking about what happened next or referring to a particular time.
For example:
Finish the application, then send it.
Here, then means the next action.
A simple check can help: if you can ask “Is this sentence comparing something?” and the answer is yes, than is the appropriate word.
When One Choice Sounds Wrong
Less then sounds wrong when it is being used as a comparison:
The drive took less then two hours. ❌
The correct version is:
The drive took less than two hours. ✅
The same applies to money:
The repair cost less then $300. ❌
The repair cost less than $300. ✅
And measurements:
The box weighs less then ten pounds. ❌
The box weighs less than ten pounds. ✅
There is one useful nuance. The words less and then can appear next to each other when they perform separate jobs.
For example:
The noise became less; then the alarm stopped.
Here, less describes the reduced noise, while then introduces the next event. They are not functioning together as the comparative phrase less than.
Common Mistakes (and Quick Fixes)
Mistake 1: Using then for a comparison
The bill was less then $50. ❌
Fix:
The bill was less than $50. ✅
Mistake 2: Assuming time requires then
A sentence about time can still require than:
The appointment lasted less than an hour. ✅
The sentence compares the duration with one hour.
Mistake 3: Treating than and then as interchangeable
They are not interchangeable. Than has a comparative function, while then commonly expresses time or sequence.
Mistake 4: Adding a hyphen to an ordinary comparison
Write:
The service costs less than $50.
Do not normally write:
The service costs less-than $50.
A hyphen can occur in a compound modifier such as less-than-perfect, but that is a different grammatical structure.
Everyday Examples
Here are natural examples from common situations.
Shopping
I found the same headphones for less than $80.
Travel
The airport is less than twenty minutes away.
Work
The presentation should take less than thirty minutes.
School
I spent less than an hour studying for the quiz.
Cooking
The recipe needs less than a cup of milk.
Technology
The file is less than 10 MB.
Fitness
The entire workout took less than forty minutes.
Quality
The result was less than impressive.
Sequence
We finished the payment and then received the confirmation.
Another sequence example
Check the address first, then click submit.
The last two examples use then because they describe the order of actions rather than a comparison.
Dictionary-Style Word Details
Verb
Less than: Not a verb. It is a comparative expression built around less.
Less then: Not a standard verb phrase. In the unusual case where less and then occur separately, neither word becomes a verb because of their position.
Noun
Less than: Not normally a noun. The expression functions as a comparative phrase.
Less then: Not a standard noun phrase. Then can have noun uses in other contexts, such as referring to a particular time, but that does not make less then a noun expression.
Synonyms
Less than: Depending on context, close plain alternatives can include under or below when referring to an amount, measurement, or limit.
For example:
The repair cost less than $100.
can be expressed in a suitable context as:
The repair cost under $100.
These alternatives are not interchangeable in every sentence.
Less then: No standard synonym is needed because it is not the normal comparative expression.
Example Sentences
Less than:
The package arrived in less than two days.
Her final score was less than expected.
The store is less than a mile away.
Less then:
The form less then is incorrect when the intended meaning is comparison.
When less and then appear separately, their functions remain separate:
The crowd became less; then the doors opened.
Word History
Less has a long history in English and is related to the older English forms that expressed a smaller amount or degree.
Than and then are historically related as well. Historical sources show that their earlier forms were closely connected, and the spelling distinction developed over time.
That historical relationship helps explain why the two modern words look so similar. Their modern grammatical roles, however, are distinct.
Phrases Containing
Less than commonly appears in expressions such as:
- less than a minute
- less than an hour
- less than expected
- less than ideal
- less than perfect
- less than $50
- less than five miles
Less then is not a standard fixed phrase for comparison.
FAQs
Is “less than” or “less then” correct?
Less than is correct when you are making a comparison. Less then is not the standard comparative phrase. Use than after less when you mean a smaller amount, number, degree, value, distance, or duration. It is the form to choose in a sentence such as “The package weighs less than five pounds.”
Can “less then” ever be correct?
The words can appear next to each other when less and then have separate jobs, but they do not form a comparative phrase. For example, “The noise became less, then the room went quiet” uses then for sequence. In that case, punctuation or sentence structure separates the ideas.
Why do people confuse “than” and “then”?
People often confuse them because the words look alike and can sound similar in ordinary speech. Their grammatical jobs differ: than introduces a comparison, while then commonly marks time, sequence, or a resulting action. The difference matters in writing.
Is “less than” used with time?
Yes. Less than is standard when comparing a duration with a stated amount of time. For example, “The meeting lasted less than an hour.” The mention of time does not make then appropriate because the sentence still expresses a comparison.
Should I use “less than” in formal writing?
Yes. Less than is standard in everyday, academic, business, and other formal writing. The choice is grammatical, not merely a matter of style. If you are comparing amounts or degrees, than is the correct word in formal contexts too.
Does “less than” always mean a number?
No. Less than can compare amounts, measurements, duration, value, degree, or quality. For example, a response can be “less than helpful,” and a trip can take “less than two hours.” The expression is broader than numerical comparisons alone.
Conclusion
For the comparison in less than or less then, the standard choice is less than.
Use than when you compare an amount, measurement, value, duration, degree, or quality:
The project took less than a week.
Use then when you describe time, sequence, or what happens next:
We finished the project, then sent the report.
The two words are easy to confuse because they look and sound similar, but their grammatical functions are different. When less introduces a comparison, choose less than.
