Aspect Ratio Calculator
Change one dimension and get the other — resize images and video without distortion.
Aspect ratio
16 : 9
Landscape · 1.7778 decimal
How to Use
- 1. Enter your original width and height, or pick a preset.
- 2. Type the new width — the height is solved automatically.
- 3. Or type the new height to solve for width instead.
- 4. Copy the resulting dimensions.
Working With Aspect Ratios
An aspect ratio is the relationship between width and height, independent of actual size. 1920×1080 and 1280×720 are both 16:9 — the same shape at different resolutions. Keeping that relationship constant is what prevents an image from looking stretched or squashed when you resize it.
The ratio is reduced by the greatest common divisor, which is why 1920×1080 displays as 16:9 rather than 1920:1080. Some dimensions do not reduce neatly — 1200×630, the standard Open Graph size, works out to 40:21 — so a decimal form is shown when whole numbers would be unhelpfully large.
Because pixels are whole numbers, a calculated dimension usually has to round, meaning the new ratio is near-identical rather than mathematically exact. The difference is visually undetectable, but the tool flags it so you know when a value was rounded.
Ready to resize? Use our Resize Image, Screenshot Beautifier, or Reduce Image Size.
Frequently Asked Questions
How do I resize an image without distorting it?
Keep the same aspect ratio. Enter your original dimensions, then type either the new width or the new height — the other value is calculated automatically so the proportions are preserved.
Why is my ratio shown as a decimal instead of whole numbers?
Some dimensions do not reduce to small whole numbers. 1200×630, for example, reduces to 40:21, while a more awkward pair produces numbers too large to be useful — in those cases a decimal ratio is clearer.
What is the difference between 16:9 and 9:16?
They are the same proportion rotated. 16:9 is landscape and suits video and desktop; 9:16 is portrait and matches phone-first formats such as Reels, Shorts, and Stories.
Why can't the new dimensions match my ratio exactly?
Pixels are whole numbers, so a calculated dimension often has to round. The result is usually within a pixel, which is visually identical — the tool tells you when the match is not exact.
What does megapixels tell me?
It is simply width × height, expressed in millions of pixels. It is a quick sanity check on output size — useful when a platform caps upload dimensions or you are budgeting file size.
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