Then vs. Than

Then and than differ by one letter and often sound similar in fast speech. The reliable fix is to identify the job the word performs, not to memorize how it looks in a phrase.

Use then for time or sequence

Then can tell when something happened: “We will review the results then.” It can show order: “Read the passage, then answer the question.” It can also signal a consequence: “If the statement is supported, then select it.” In each case, the sentence moves through time, steps, or logic.

Use than for comparison

Than introduces the second part of a comparison: “The revised sentence is clearer than the first one.” Comparisons can involve adjectives, adverbs, quantities, or choices: “She writes more carefully than before.” If the sentence compares two people or things, than is usually the word you need.

Check common sentence patterns

• No sooner had the bell rung than the students began writing.
• The second explanation is more concise than the first.
• Finish the outline, then revise the introduction.
• Rather than guessing, compare the evidence with the claim.

A quick editing check

Replace the word with “after that” or “at that time.” If the sentence keeps its meaning, then may fit. If the sentence means “in comparison with,” use than. Some set phrases require than even when the comparison is implicit, so read the whole sentence rather than relying on a one-word swap.

Use the sentence structure as evidence

Then can function as an adverb for a later time (“We will meet then”), a next step (“Check the labels, then compare the totals”), or a logical consequence (“If the premise is true, then the conclusion follows”). Than is a conjunction or preposition introducing the other side of a comparison: “The second route is longer than the first.” Find the relationship between the surrounding ideas before choosing the spelling.

Some comparisons omit words that are understood. “She is taller than I” is traditionally expanded to “She is taller than I am”; informal speech may use “than me.” The choice of pronoun is a separate grammar question. The word than is still correct because it introduces the comparison. In a phrase such as “rather than,” it marks an alternative even when the sentence is not comparing two adjectives.

Recognize the paired construction

The pattern no sooner … than links two events: “No sooner had the meeting ended than the calls began.” It does not mean “next, the calls began” in the ordinary sequence sense. The word than is part of a fixed comparison-like construction. Similarly, “more than,” “less than,” and “other than” use than to introduce a comparison, quantity boundary, or exception.

Avoid sound-based substitutions

• “I would rather revise than submit a draft” uses than to introduce the alternative.
• “Finish the first problem, then start the next” uses then for sequence.
• “The result was higher than expected” uses than for comparison.
• “The argument is stronger now than it was before” compares two states.
• “If the evidence supports the claim, then the conclusion is reasonable” uses then for a conditional result.

A four-step editing routine

1. Underline the words or ideas connected by then or than.
2. Ask whether the sentence means next/at that time/as a result, or whether it compares alternatives or amounts.
3. Try “after that” for then or “in comparison with” for than, checking the full sentence.
4. Read the sentence once more to catch a second issue, such as a missing comparison target or faulty parallel structure.

The last check matters in sentences such as “The proposal costs less than installing the old system.” The intended comparison is likely between the proposal's cost and the cost of installing the old system, so a clearer version is “The proposal costs less than installing the old system would cost.” Choosing than correctly does not by itself make the comparison complete or logically parallel.

Use than for comparison

Than introduces the second item in a comparison: “The second section was shorter than the first.” It commonly follows comparative words such as taller, more useful, less costly, better, and rather. Ask “compared with what?” If the sentence is comparing people, quantities, qualities, or choices, than is usually correct.

Comparisons should be parallel and clear: “Maya reads more carefully than Lee does” compares how two people read. “Maya reads more carefully than Lee” may be understood, but the first version makes the comparison explicit. Avoid comparing unlike things, such as a person with a study plan, unless the intended relationship is clear.

Use then for time or sequence

Then refers to time, sequence, or a consequence: “Review the instructions, then begin the test”; “If the sample is complete, then calculate the average.” It can mean at that time, next, or in that case. A time expression with then can describe a past or future point: “I lived there then.”

In if-then statements, then is often optional: “If x is 4, then y is 9” and “If x is 4, y is 9” are both grammatical. Than cannot introduce that consequence. Use the sentence’s logical role rather than pronunciation, since then and than sound similar in many accents.

Check the phrase before finalizing

A useful proofread is to replace than with compared with and then with next or at that time. If the replacement preserves the intended relationship, the spelling is probably correct. Also look for common fixed expressions: rather than, other than, and no sooner…than all use than. Read the complete sentence because local word pairs can guide but not guarantee the choice.

• Than follows comparative language and introduces a comparison.
• Then indicates time, sequence, or consequence.
• Use parallel elements in comparisons.
• Test than with compared with and then with next or at that time.
• Remember fixed phrases such as rather than and no sooner than.

Exam takeaway

Then marks when, next, or therefore. Than marks comparison. Ask what relationship the sentence expresses, and check that the surrounding grammar supports it.

Use the concept in a question

Than introduces a comparison: “The second passage is longer than the first.” Then usually refers to time, order, or a next step: “Read the prompt, then outline your response.” The words can sound similar but perform different grammatical jobs. A quick substitution test helps: if “next” fits, then is likely correct; if the sentence compares two things, use than. In a sentence such as “No sooner had the bell rung than class began,” than is part of a comparison-like correlative construction and cannot be replaced with then. Proofread each occurrence according to the relationship the sentence expresses.