souvssumWhat's the difference?

Which to use

“sou” and “sum” are a confusable English pair: similar on the page, but distinct in meaning, check the gloss before you choose.

#35,525
“sou” frequency rank
#4,050
“sum” frequency rank
39575
confusion score

Side-by-Side Comparison

Feature sou sum
Definition An old French copper coin equal to one twentieth of a livre or twelve deniers; one sou is to the livre as one shilling is to the pound. A quantity obtained by addition or aggregation.

Where the eye mixes sou and sum

Muted = shared; highlighted = the visual trap. They share 2 letters in sequence.

3 ch
sou
3 ch
sum

Look-alike desk: sou vs sum

A purely visual mix-up. sou (/suː/) and sum (/sʌm/) are said differently, so reading them aloud is the quickest way to catch the wrong one. On the page they stay close: they share most of their letters but differ in 2 positions. Our composite confusion score for this pair is 39575, derived from the frequency rank of both members and their visual similarity.

sou is recorded at frequency rank #35,525, classified as anoun, pronounced /suː/. sum is at rank #4,050, tagged as anoun, pronounced /sʌm/.

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 39575, this pair ranks #275,427 of 530,003 scored English confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of sou vs sum

Shared letters: su. Private to "sou": o. Private to "sum": m.

"sou" · 3 letters · shape CVV  ·  "sum" · 3 letters · shape CVC

Frequently Asked Questions

Can "sou" and "sum" be used interchangeably?
No. They are said differently (/suː/ versus /sʌm/) and carry different meanings; reading the sentence aloud is usually enough to catch the wrong one.
In ordinary English text, does "sou" or "sum" show up more?
"sum" is the more common of the two: it sits at frequency rank #4,050 in our English list, against #35,525 for "sou". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Useful next steps

Pronunciation already separates them, if the page still looks alike, the dictionary links below settle it.

  • Full dictionary entry for "sou" with definition, IPA, and generated misspellings. Word entry
  • Full dictionary entry for "sum" - compare definitions side by side with the headword page. Word entry
  • This pair ranks #275,427 of 530,003 scored English confusable pairs in this corpus vintage. Corpus statistics
  • "sou" and "sum" also get mixed up with nearby pairs, the highest-scored neighbour is "Sif vs sou". Nearby pair

Confusion rank #275,427 of 530,003 scored English pairs, corpus vintage 2026-09-03, not spelling advice.

Source: Wiktionary (via kaikki.org) Structured Wiktionary extract

Source: FrequencyWords open word-frequency list