Which to use
“per” is a preposition and “ppm” is an abbrev - they look or sound alike but fill different roles in a sentence.
- #673
- “per” frequency rank
- #40,761
- “ppm” frequency rank
- 41434
- confusion score
Side-by-Side Comparison
| Feature | per | ppm |
|---|---|---|
| Definition | mittels | Mengeneinheit/Quotient, die die Konzentration eines Stoffs in einem anderen Stoff angibt; für Englisch parts per million, für Anzahl Teilchen in einer Million Teilchen; 1 ppm = 0,001 ‰ = 0,0001 %; Veranschaulichung: 1 ppm = etwa 5 Wassertropfen (á 0,05 ml) auf eine Badewanne mit Wasser (á 250 l) |
Where the eye mixes per and ppm
Muted = shared; highlighted = the visual trap. They share 1 letter in sequence.
Why the eye confuses per with ppm
These two trip readers on the page rather than in the ear: per is [pɛʁ] while ppm is [peːpeːˈʔɛm]. Spoken aloud the problem disappears. In writing it persists, because they share most of their letters but differ in 2 positions, and the parts of speech differ too (preposition vs abbrev), which is usually the fastest check. Our composite confusion score for this pair is 41434, derived from the frequency rank of both members and their visual similarity.
per is recorded at frequency rank #673, classified as aprep, pronounced [pɛʁ]. ppm is at rank #40,761, tagged as anabbrev, pronounced [peːpeːˈʔɛm].
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 41434, this pair ranks #1,479,531 of 2,006,359 scored German confusable pairs - roughly mid-pack for confusability.
Orthographic DNA of per vs ppm
Shared letters: p. Private to "per": er. Private to "ppm": m.
"per" · 3 letters · shape CVC · "ppm" · 3 letters · shape CCC
Frequently Asked Questions
Can "per" and "ppm" be used interchangeably?
In ordinary German text, does "per" or "ppm" show up more?
Useful next steps
Visual near-miss handled. Browse the word pages or a neighbour when the next look-alike shows up.
- Full dictionary entry for "per" with definition, IPA, and generated misspellings. Word entry
- Full dictionary entry for "ppm" - compare definitions side by side with the headword page. Word entry
- This pair ranks #1,479,531 of 2,006,359 scored German confusable pairs in this corpus vintage. Corpus statistics
- "per" and "ppm" also get mixed up with nearby pairs, the highest-scored neighbour is "PMS vs ppm". Nearby pair
Confusion rank #1,479,531 of 2,006,359 scored German pairs, corpus vintage 2026-09-03, not spelling advice.