Aspect Ratio Calculator — Resize, Keep the Shape

← Palette AtollThe Creative Island · Island 09

Know your ratio, keep it — resize images and video without distortion.

Width (px)

Height (px)

New width → matching height

How to use this tool

1. Enter your original width and height — the simplified ratio appears (e.g. 16:9).
2. Enter a new width to get the matching height — or the reverse.
3. The result keeps the exact shape; no stretching, no cropping.

Example

1920 × 1080 → 16:9. New width 1280 → height 720. For a 1080-wide version: 1080 × 608 (rounded from 607.5) — always re-round at the end, never mid-way.

The formula

ratio = width ÷ gcd × ':' × height ÷ gcd  |  new height = new width × (height ÷ width)

What the result means

The simplified ratio (dividing both numbers by their greatest common divisor) is the shape's true name — 1920×1080 and 1280×720 are the same 16:9 shape. Resizing that keeps the ratio preserves composition; breaking it stretches faces and circles, the two things viewers notice first.

Frequently asked questions

My ratio comes out weird, like 683:384 — why?

The numbers share no common divisor (683 is prime). The shape is still valid — it is simply not one of the famous ratios; the decimal form is often more useful.

What ratio should YouTube thumbnails use?

16:9 (1280×720 is the standard) — enter those numbers here to verify any custom size.

Why does 1080 wide give 608 high, not 607.5?

Pixels are whole; the tool rounds to the nearest integer. For print and print-quality work, keep the fraction through the pipeline instead.

Is anything uploaded?

No — pure arithmetic in your browser.

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Explore the island world

• Palette Atoll — the island where this tool lives.
• The Main Island — drive the boat, explore the whole world.
• The 90s Kids Island — where most of us started.

Privacy & data: this tool runs entirely in your browser — nothing you type is uploaded, saved or sent anywhere. · Disclaimer: color values are computed with standard formulas; final appearance always depends on the display and medium. · Privacy Policy · Disclaimer