Aspect Ratio Calculator
Calculate ratio from width and height
Input
Common ratios
Common sizes
Result
- Aspect ratio
- Common name
- Decimal ratio
- Width / height percent
Everything is calculated in your browser. Entered values are not sent to a server.
How to use
Enter a width and height and get the aspect ratio reduced to its simplest whole numbers, along with how close it is to a familiar ratio such as 16:9. Lock a ratio and filling in one side computes the other. Nothing is uploaded.
When to use it
- Finding sizes that match a target ratio for video or images.
- Checking what ratio 1920×1200 actually is.
- Resizing while keeping the proportions.
How to use it
- Enter the width and height.
- The ratio, decimal ratio, percentage and any common name appear immediately.
- The preset buttons offer 16:9, 4:3, 1:1 and others.
- Lock a ratio and the other side follows whenever you change one.
Good to know
- Ratios are reduced to their simplest whole numbers (1920×1080 → 16:9).
- When a target ratio does not land on whole pixels, you get both the exact value and the rounded one, because screen sizes must be integers.
- Familiar ratios are marked as exactly equal or merely close — "close" is not the same number.
- All calculations happen in your browser.
Frequently asked questions
Is 1920×1200 16:10?
Yes, exactly. 1920 ÷ 1200 = 1.6, and so does 16 ÷ 10. The tool reduces to simplest terms, so it may show 8:5 — the same ratio written more simply.
What does the rounding note mean?
An exact fit sometimes needs a fraction of a pixel: at 16:9 a width of 1000 wants a height of 562.5. Screen sizes must be whole numbers, so it rounds to 563 and tells you the exact value too.
Does "close" mean the same?
No. 1.777… and 1.78 are similar but different. In video work, using a merely close value can produce black bars.
Does it handle portrait video?
Yes. When the height exceeds the width you get a portrait ratio such as 9:16, which is what short-form video uses.