Aspect Ratio Calculator
Calculate the aspect ratio of a width and height, or solve for a missing dimension given a ratio. Includes common ratios like 16:9, 4:3, 1:1 and more.
How it works
An aspect ratio is a ratio of width to height. The calculator has three modes:
- From width & height: enter any two dimensions and get the simplified ratio (e.g. 1920×1080 → 16:9).
- From width & ratio: enter a width and a target ratio to compute the matching height.
- From height & ratio: enter a height and a target ratio to compute the matching width.
Common ratios
- 16:9 — HD video, modern monitors
- 4:3 — classic TV and some compact cameras
- 1:1 — square (Instagram, profile photos)
- 9:16 — vertical video (TikTok, Reels, Shorts)
- 3:2 — 35mm photography, many mirrorless cameras
- 21:9 — ultrawide cinema and monitors
Examples
Quick examples:
- 1920×1080 → 16:9
- 1080×1920 → 9:16
- 4032×3024 → 4:3
- 3000×2000 → 3:2
- 3440×1440 → 43:18 (≈ 21.5:9)
Frequently asked questions
An aspect ratio describes the proportional relationship between an image's width and its height. It is written as
width:height (e.g. 16:9) and stays the same regardless of the actual pixel dimensions.Divide the width and height by their greatest common divisor (GCD). For example, 1920 × 1080 has a GCD of 120, so 1920/120 : 1080/120 = 16:9.
16:9 is the standard aspect ratio for HDTV, most online video, modern monitors, and YouTube. 1920×1080, 2560×1440 and 3840×2160 (4K) are all 16:9.
9:16 is the vertical version of 16:9. It is the standard for vertical video on TikTok, Instagram Reels, YouTube Shorts and similar platforms.
21:9 is an ultrawide aspect ratio used by ultrawide monitors and some cinema content. It is wider than 16:9, giving more horizontal screen space.