Aspect Ratio Calculator
Lock a ratio, enter width or height in pixels, and get the matching dimension instantly — with a live shape preview.
Presets
Quick sizes
Change either pixel field and the other updates to keep the ratio. Ratio fields stay editable — editing them switches the preset to Custom.
Common ratios
16:9
YouTube, modern TVs, presentations, and most laptop displays.
9:16
TikTok, Reels, Shorts, and phone-first vertical video.
21:9
Ultrawide monitors and cinematic widescreen frames.
3:2 / 4:3 / 1:1
Photography, classic monitors, and social avatars.
Frequently Asked Questions
What is aspect ratio?
It is the width-to-height proportion of an image or frame. 16:9 means 16 units wide for every 9 units tall.
Should I crop or pad?
Crop when the center matters and you can lose edges. Pad (letterbox/pillarbox) when you must keep all content visible.
Does this upload files?
No. This page only does math in your browser.