Then and than look nearly identical, sound similar in rapid speech, and are among the most frequently confused word pairs in English. The difference, however, is straightforward once you understand the rule: then relates to time or sequence; than is for comparisons. This guide covers the rule, common mistakes, and memory tricks that make the distinction automatic.
The One-Rule Summary
Then = time or sequence (what happens next). Than = comparison (comparing two things). If you can replace the word with "next" or "at that time," use then. If you can replace it with "compared to," use than.
Then: Time, Sequence, and Consequence
Sequence of events: "We reviewed the contract, then we signed it." Then marks what happened next.
Specific time reference: "I was younger then." "Back then, we didn't have smartphones." Then refers to a time already mentioned or understood.
Conditional consequence (if/then): "If you finish early, then we can grab dinner." Then introduces the result of a condition.
Addition or emphasis: "The rent, and then the utilities on top of that..." Then adds another item, often with frustration or emphasis.
Than: Comparisons Only
Comparative adjectives: "She's taller than her brother." "This route is faster than the highway." Than always follows a comparative form (taller, faster, better, more, less).
"Rather than" and "other than": "I'd rather walk than take the bus." "No one other than the manager can approve this." These fixed phrases always use than.
"More than" / "Less than": "It costs more than I expected." "The meeting lasted less than an hour." These quantity comparisons always use than.
Common Mistakes and Corrections
Wrong: I'm taller then you.
Right: I'm taller than you. (Comparison — use than.)
Wrong: First we eat, than we leave.
Right: First we eat, then we leave. (Sequence — use then.)
Wrong: It was more expensive then I thought.
Right: It was more expensive than I thought. (Comparison — use than.)
Wrong: Back than, things were different.
Right: Back then, things were different. (Time reference — use then.)
Memory Tricks That Work
Trick 1: The "E" and "A" Mnemonic. Then = Time. Both have an "e." Than = Comparison. Both have an "a." This is the simplest, most reliable trick.
Trick 2: The Alphabet Test. In the alphabet, "e" comes before "a." In a sequence of events, then (with "e") comes before than (with "a") — first something happens, then you compare it.
Trick 3: The Replacement Test. Read the sentence aloud. Replace the word with "next" — if the sentence still makes sense, use then. Replace with "compared to" — if it still works, use than. The replacement that sounds natural tells you which spelling to use.
Then/Than in Formal Writing
In academic and professional writing, then/than errors are considered basic mistakes that undermine credibility. A 2023 Grammarly analysis of 50 million documents found then/than confusion was the 8th most common writing error among native English speakers. Proofreading specifically for this pair — scanning your draft and checking every instance of then and than — catches 95% of these errors before anyone else sees them.