Aspect Ratio Calculator
Calculate ratio from dimensions, or find a missing dimension from a known ratio.
Dimensions → Ratio
×
16:9
Decimal: 1.778
16:9
Common presets
Find Missing Dimension
:
px
Formula
Ratio = width : height, simplified by dividing both by GCD Missing dimension = known × (ratio H ÷ ratio W)
- GCD (–) — Greatest Common Divisor of width and height
Example: 1920 × 1080 → GCD(1920,1080) = 120 → ratio = 16:9
Interpreting Your Result
16:9
Widescreen (HD/4K)
Standard for TVs, YouTube, most monitors
4:3
Traditional
Older monitors, photography
21:9
Ultra-wide
Cinema and ultra-wide monitors
1:1
Square
Instagram posts, profile pictures
9:16
Portrait/vertical
Stories, TikTok, Reels
Frequently Asked Questions
What is the most common aspect ratio?
16:9 is the dominant ratio for HD and 4K screens. It's the standard for YouTube, streaming, and most desktop monitors.
What aspect ratio is a phone screen?
Most modern smartphones use 19.5:9 to 20:9 (taller than traditional widescreen), though they display 16:9 content with letterboxing.