dup vs duty, What's the Difference?

Which to use

“dup” is a verb and “duty” is a noun - they look or sound alike but fill different roles in a sentence.

#28,177
“dup” frequency rank: #1,994
“duty” frequency rank: 30171
confusion score

Side-by-Side Comparison

Feature	dup	duty
Definition	to open (a door, gate etc.)	That which one is morally or legally obligated to do.

Where the spellings diverge

Shared letters are muted; the letters that actually set dup and duty apart are highlighted. They share 2 letters in sequence, which is exactly why the eye skips the difference.

3 ch

dup

4 ch

duty

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: dup is /dʌp/ while duty is /ˈdjuː.ti/. 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 (verb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 30171, derived from the frequency rank of both members and their visual similarity.

dup is recorded at frequency rank #28,177, classified as averb, pronounced /dʌp/. duty is at rank #1,994, tagged as anoun, pronounced /ˈdjuː.ti/.

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 30171, this pair ranks #356,788 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of dup vs duty

Shared letters: du. Private to "dup": p. Private to "duty": ty.

"dup" · 3 letters · shape CVC · "duty" · 4 letters · shape CVCV

Known mistypes of this pair

duty ← dduty · dtuy · dutty · dutyy · duyt · udty

Frequency comparison

dup#28,177

duty#1,994

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "dup" and "duty" be used interchangeably?

No - they are not even the same part of speech. "dup" is a verb and "duty" a noun, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "dup" or "duty"?

"duty" is the more common of the two: it sits at frequency rank #1,994 in our English list, against #28,177 for "dup". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Remembering dup vs duty

The fastest way to pick the right one every time.

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