to blank then (than) by

Writers mix then and than because they sound alike but serve different jobs: then = time/sequence/result; than = comparison. Use quick substitution tests and the ready rewrites below to fix sentences immediately.

If you need a quick check, replace the suspect word with "after" or "next" - if that fits, use then. If the sentence compares amounts, size, preference, or choices, use than.

Short answer

Then marks time, order, or consequence. Than marks comparison. Replace the word with "after" or "next" to test for then; if you're comparing two things, use than.

Then = time / sequence / consequence (e.g., then we left; if/then; back then).
Than = comparison (e.g., taller than; more than; rather than).
Substitution test: "after/next" → then. Comparison cues (more, less, rather, prefer) → than.

Core explanation: the grammatical difference

Then is an adverb that places actions in time or links cause and effect. Than is a conjunction or preposition used only for comparisons.

Ask: is the sentence about when something happens or about comparing two things? That decides which word to use.

Then = when / next / after / as a result.
Than = comparing degree, quantity, preference, or choice.

Wrong: She finished her degree then went abroad.
Right: She finished her degree, then went abroad.
Wrong: He is smarter then his sister.
Right: He is smarter than his sister.

Spacing and typing errors to check first

Typos and spacing problems often look like grammar mistakes. Fix those before testing meaning.

Watch for split words (t hen), stray underscores (to__then_by), or repeated letters (thenn).
Correct obvious spacing or punctuation errors, then apply the substitution test.

Wrong: The offer is better then__expected.
Right: The offer is better-than-expected.
Wrong: If you arrive th en call me.
Right: If you arrive, then call me.

Hyphenation and compound modifiers

When a comparison phrase modifies a noun before it, hyphenate the phrase: better-than-expected result. After the noun, no hyphen is needed.

Hyphens don't change whether you use then or than: comparisons use than; time/sequence use then.

Before a noun: better-than-expected outcome (use hyphens).
After a noun: the outcome was better than expected (no hyphen).
If the meaning is time or sequence, don't use than; hyphenation is irrelevant.

Wrong: A then-expected arrival time is unusual.
Right: A better-than-expected arrival time lifted morale.
Wrong: This is more then-typical behavior.
Right: This is more-than-typical behavior.

Memory tricks that work

Use one simple habit: substitution. Replace the suspect word with "after" or "next." If the sentence still makes sense, you likely need then. If the sentence is comparing, use than.

Another quick cue: then contains an "e" like "event" (time); than contains an "a" like "amount" (comparison).

Substitution test: "after"/"next" → then; "more"/"less"/"rather" → than.
Listen for comparison words: more, less, rather, prefer, taller, better.
If unsure, rewrite into two short sentences to remove ambiguity.

Example: "We'll eat after we finish." If you tried "We'll eat next we finish," the meaning calls for "after" or a rewrite: "We'll eat after we finish." Or: "We'll eat, then we'll celebrate."
Example: "I like X more than Y." The comparison word "more" signals than.

Try your own sentence

Test the whole sentence, not just the phrase. Context often makes the correct choice obvious.

Examples by context: work, school, casual (copy these fixes)

Grouped examples show common traps and their corrections. Use the corrected sentence when it matches your meaning.

Work examples focus on sequence (then) and comparative analysis (than).
School examples show comparisons in essays and sequence in procedures.
Casual examples show quick messages where people often pick the wrong form.

Work - Wrong: We'll review the draft than send it to legal.
Right: We'll review the draft, then send it to legal.
Work - Usage: Q3 revenue was higher than Q2, so we will revise projections.
Work - Usage: Complete the form, then upload it to the portal.
School - Wrong: More then half the sample failed the control test.
Right: More than half the sample failed the control test.
School - Usage: First summarize the chapter, then answer the questions at the end.
School - Usage: Newton's laws are more useful than anecdotes for this analysis.
Casual - Wrong: See you then that sounds good.
Right: See you then - that sounds good.
Casual - Usage: I'd rather stay home than go out tonight.
Casual - Wrong: Back than, we didn't have smartphones.
Right: Back then, we didn't have smartphones.

How to rewrite your sentence in three quick checks

Follow three steps: role → substitute → tidy. The aim is a fix you can paste immediately.

Step 1 - Role: Is it about time/sequence/result or a comparison? Time → then. Comparison → than.
Step 2 - Substitute: Try "after" or "next" for then; try rephrasing as "X is bigger than Y" for than.
Step 3 - Tidy: Add punctuation (comma before then if it starts an independent clause) or shorten the sentence if it's ambiguous.

Rewrite:
Wrong: We improved then the client signed. →
Right: We improved, then the client signed the contract.
Rewrite:
Wrong: He would rather study then go out. →
Right: He would rather study than go out.
Rewrite:
Wrong: Submit the form than contact HR. →
Right: Submit the form, then contact HR.

Quick repair: ready-made rewrites you can copy

Use these when you need a fast, correct replacement without rethinking the sentence.

Wrong: We left than we realized. Copy: We left sooner than we realized.
Wrong: If approved then proceed. Copy: If approved, then proceed.
Wrong: She was more then willing to help. Copy: She was more than willing to help.
Wrong: Finish the checklist then submit. Copy: Finish the checklist, then submit it.

Similar mistakes to fix at the same time

Writers who mix then and than often trip over other short words. Check these in the same pass.

their / they're / there - possession vs contraction vs place.
its / it's - possessive vs it is.
affect / effect - verb vs noun; choose by meaning.
to / too / two - direction vs also vs number.

Usage: Wrong: Its later then I thought.
Right: It's later than I thought.
Usage: Wrong: They're reasons then results.
Right: Their reasons came first, then the results followed.

FAQ

When should I use then vs than?

Then for time, sequence, or consequence (after, next, therefore). Than only for comparisons (bigger than, more than, rather than). Run the substitution test: "after/next" → then; otherwise use than when comparing.

Is there ever a case where both words could be correct?

Not for the same meaning. If a sentence could be read either way, rewrite it to remove ambiguity - split it or rephrase.

How do I punctuate before then?

If then begins an independent clause, use a comma before it: "We planned it, then we executed." If it's part of a short phrase ("back then"), no comma is needed.

Can spellcheck catch then/than errors?

Basic spellcheck won't catch context errors. Use the substitution test or a short rewrite for reliable results.

Quickest habit to stop the mistake?

Make the substitution test a reflex: ask "after/next?" If yes, type then. If you're comparing, type than. When in doubt, rewrite into two clear sentences.

Fix one sentence now

Paste your sentence into your document, run the three checks above, or copy one of the ready-made rewrites. Small edits - a substitution or a comma - fix most errors quickly.