Aspect Ratio Calculator
FreeCalculate and convert aspect ratios and dimensions instantly.
Runs entirely in your browser. Nothing you enter is uploaded or stored.
How it works
What is an aspect ratio?
The proportional relationship between a shape's width and height, written as two numbers separated by a colon. 16:9 is standard widescreen video, 4:3 was the standard for older TVs and monitors, and 1:1 (square) is common for social media posts — the actual pixel dimensions can vary widely while the ratio between width and height stays the same.
How do the two calculator modes work?
"Dimensions from ratio" takes a ratio (like 16:9) plus either a width or a height, and computes the other dimension so the pair matches that ratio exactly. "Ratio from dimensions" does the reverse: given a width and height, it reduces them to the simplest exact integer ratio using genuine GCD-based simplification — not a lookup against a fixed list of common ratios — so an unusual resolution like 2560×1600 correctly simplifies to 8:5 rather than being forced to the nearest familiar ratio like 16:9.
Why does the result show a "nearest common ratio" sometimes?
When your dimensions don't exactly match a well-known standard ratio, the tool shows which standard ratio is numerically closest — useful context for choosing a familiar target ratio — without ever pretending it's an exact match when it isn't.
Does this tool store or upload anything I enter?
No. Every calculation happens entirely in your browser. Nothing is sent to a server, logged, or saved.