fast vs fay, What's the Difference?

Which to use

“fast” is an adverb and “fay” is a noun - they look or sound alike but fill different roles in a sentence.

#243
“fast” frequency rank: #46,636
“fay” frequency rank: 46879
confusion score

Side-by-Side Comparison

Feature	fast	fay
Definition	nicht ganz	eine Fee

Where the spellings diverge

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

4 ch

fast

3 ch

fay

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: fast is [fast] while fay is [feɪ]. 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 (adverb vs noun), which is usually the fastest check. Our composite confusion score for this pair is 46879, derived from the frequency rank of both members and their visual similarity.

fast is recorded at frequency rank #243, classified as anadv, pronounced [fast]. fay is at rank #46,636, tagged as anoun, pronounced [feɪ].

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 46879, this pair ranks #1,303,798 of 2,006,359 scored German confusable pairs - roughly mid-pack for confusability.

Orthographic DNA of fast vs fay

Shared letters: af. Private to "fast": st. Private to "fay": y.

"fast" · 4 letters · shape CVCC · "fay" · 3 letters · shape CVV

Known mistypes of this pair

fast ← afst · fastt · fats · ffast · fsat

Frequency comparison

fast#243

fay#46,636

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "fast" and "fay" be used interchangeably?

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

Which is more common, "fast" or "fay"?

"fast" is the more common of the two: it sits at frequency rank #243 in our German list, against #46,636 for "fay". That is a wide gap, so in ordinary text the rarer spelling is the one worth double-checking.

Remembering fast vs fay

The fastest way to pick the right one every time.

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