In, on or at? Zoom in.
For time, think zoom levels: a month, a day, a moment. For place, think shapes: a container, a surface, a point. Then test yourself with a short quiz.
My birthday is in May.
The widest zoom level: months, years, seasons. in May →
In, on or at? Answer two questions.
Think of the phrase you want to say.
In, on and at at a glance
Three words, two rules. Each picture shows when to use it.
The pairs people mix up
You understand it. Now find it in your own writing.
Paste an email or an essay. Clarigram marks the mistakes you actually make, shows the rule behind each one as a picture, and builds your practice from them.
Questions people ask
How do I choose between in, on and at for time?
Think in zoom levels: in for long periods (in May, in 2026), on for days and dates (on Monday, on 3 June), at for exact times (at 9:00). Before next, last, this and every, use no preposition.
How do I choose between in, on and at for place?
In for inside a space or an area (in the kitchen, in Cluj), on for a surface or a line (on the table, on the wall), at for a point or a place where you do something (at the bus stop, at work).
Are prepositions the same in British and American English?
Mostly. A few differ: at the weekend (British) vs on the weekend (American), and in the street (British) vs on the street (American). Both versions are correct.