Aspect Ratio Calculator
GCD-reduced ratio, or height = width × (h/w). Click any i for detail.
Frame
Mode
i
Mode
Pixels → ratio, or ratio + width → height. |
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|---|---|
Width (px)
i
Width
Pixel width. |
|
Height (px)
i
Height
Pixel height. |
|
Ratio width
i
RW
16 in 16:9. |
|
Ratio height
i
RH
9 in 16:9. |
|
Width (px)
i
Width
Known pixel width. |
How to use this calculator
- Pick pixels→ratio or ratio+width→height.
- Enter pixel dimensions or ratio numbers.
- Read reduced ratio or missing edge length.
- Use reduced ratio for CSS or export presets.
Results explained
1920×1080 reduces to 16:9 by dividing both by gcd. Height-from-width mode scales pixels: h = w × RH/RW.
Quick reference: aspect ratios
1920×1080, 1280×720, and 3840×2160 are all 16:9.
| Item | Detail |
|---|---|
| 16:9 | HD and UHD video |
| 4:3 | classic TV and iPad portrait-ish frames |
| 1:1 | square social crops |
| 9:16 | vertical phone video |
Non-square pixels (DAR vs SAR) are ignored.
How the estimate is built
reduce w:h by gcd(w,h); height = width × (RH/RW).
Example scenario
1920×1080 → 16:9.
FAQ
Is aspect ratio the same as resolution?
No. Ratio is shape; resolution is pixel count. 1280×720 and 1920×1080 share 16:9.
Print DPI?
This page stays in pixels; print sizing needs DPI separately.
Can width be smaller than height?
Yes. 1080×1920 reduces to 9:16 vertical.