their vs then, What's the Difference?

Which to use

“their” is a determiner and “then” is an adverb - they look or sound alike but fill different roles in a sentence.

#56
“their” frequency rank: #91
“then” frequency rank: 147
confusion score

Side-by-Side Comparison

Feature	their	then
Definition	Belonging to, from, of, or relating to, them (plural).	At that time.

Where the spellings diverge

Shared letters are muted; the letters that actually set their and then apart are highlighted. They share 3 letters in sequence, which is exactly why the eye skips the difference.

5 ch

their

4 ch

then

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: their is /ðɛə/ while then is /ðɛn/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (determiner vs adverb), which is usually the fastest check. Our composite confusion score for this pair is 147, derived from the frequency rank of both members and their visual similarity.

their is recorded at frequency rank #56, classified as adet, pronounced /ðɛə/. then is at rank #91, tagged as anadv, pronounced /ðɛn/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 147, this pair ranks #529,817 of 530,003 scored English confusable pairs - a relatively easy-to-tell-apart pair.

Orthographic DNA of their vs then

Shared letters: eht. Private to "their": ir. Private to "then": n.

"their" · 5 letters · shape CCVVC · "then" · 4 letters · shape CCVC

Known mistypes of this pair

their ← hteir · tehir · theirr · theri · thheir · ttheir
then ← hten · tehn · thenn · thhen · thne · tthen

Frequency comparison

their#56

then#91

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "their" and "then" be used interchangeably?

No - they are not even the same part of speech. "their" is a determiner and "then" an adverb, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "their" or "then"?

"their" is the more common of the two: it sits at frequency rank #56 in our English list, against #91 for "then". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Remembering their vs then

The fastest way to pick the right one every time.

Check the role first: if you need a determiner, it's “their”; for an adverb, it's “then”.
See each word in full, definition, IPA, etymology and its other confusables. Full “their” entry
Browse more pairs most likely to be confused. Most confusable