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Prepositions after adjectives

Fast on, for, in, with, or at?

Fast combines with different prepositions depending on meaning. Some combinations are fixed expressions, while others introduce context or ability.

Quick answer

Common patterns with fast

Use fast at for skill, fast with for handling something quickly, and fast on in fixed expressions such as fast on a surface. Fast for compares speed with expectations. Fast in usually introduces a context or activity.

She is fast at mental arithmetic.
He is fast with a keyboard.
The label stays fast on metal surfaces.

Choose the pattern by meaning

These forms are not interchangeable. Choose the construction by meaning, not by which preposition appears most often.

1
fast at + activity

Showing skill or speed in an activity

Use fast at to describe someone who performs an activity quickly.

My sister is fast at typing.
He became fast at solving puzzles.
2
fast with + tool/object

Handling something quickly

Use fast with to describe quick use of a tool, device, or method.

She is fast with spreadsheets.
The chef is fast with a knife.
3
fast on + surface

Fixed firmly to a surface

Fast on is a less common but standard expression meaning firmly attached.

The paint holds fast on wood.
The sticker stayed fast on the window.
4
fast for + noun

Comparing expected speed

Use fast for when comparing with a standard or category.

The boat is fast for its size.
She runs fast for a beginner.

See the difference in context

The same subject can take different constructions because each sentence answers a different question.

Construction
Example
Meaning
fast at
He is fast at calculations.
quick in performing an activity
fast with
She is fast with design software.
quick when using something
fast on
The colour stays fast on fabric.
firmly fixed or resistant to fading
fast for
That laptop is fast for its age.
faster than expected for a category
fast in
He is fast in emergencies.
in introduces a situation or context

Common mistakes

Some combinations appear in real text but do not mean what learners often assume.

Using fast in for ability

Use fast at for activities and skills.

✕ She is fast in maths. ✓ She is fast at maths.

Confusing fast on with speed

Fast on often means firmly attached, not quick movement.

✕ The runner was fast on the track. ✓ The runner was fast on the track by noon.

Using with after general activities

With usually refers to tools or objects.

✕ He is fast with cooking. ✓ He is fast at cooking.

Quick practice

Choose the expression that matches the intended meaning.

1. She is fast ___ data entry.
2. The colour remains fast ___ cotton.
3. The car is fast ___ a small engine.

Check your sentence in context

Paste the complete sentence below. Linguix checks the preposition together with grammar, spelling, punctuation, and style.

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Frequently asked questions

Is fast at correct English?

Yes. It means someone performs an activity quickly.

What does fast on mean?

It can mean firmly attached or resistant on a surface, especially in technical or material contexts.

Can I say fast with computers?

Yes. It means someone uses computers quickly or efficiently.

face-to-face-with-in-at-for, to "fair to" or "fair in"? faithful to, in, of, with or for? falling of, in, out, into or off? "false in" or "false to"? famed for, as, in or throughout? familiar with, to, from or in? famous for, in, of, by or as? fanatical about, in, as, for or of? "fantastic for" or "fantastic in"? far from, in, to, for or with? fascinating to, about, in, for or as?

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