Common Aspect Ratios Compared
Aspect ratio describes the proportional relationship between width and height. The chart below compares six widely-used ratios — from ultrawide cinema to mobile portrait. Click any bar to load that ratio into the calculator.
Click a bar to try that ratio in the calculator ↑
Platform Size Reference
Each platform renders images at a specific ratio. Mismatched proportions cause automatic cropping or letterbox bars.
| Platform | Ratio | Recommended Size |
|---|---|---|
| YouTube | 16:9 | 1920×1080 |
| Instagram Feed | 1:1 / 4:5 | 1080×1080 / 1080×1350 |
| TikTok / Reels | 9:16 | 1080×1920 |
| Twitter/X Header | 3:1 | 1500×500 |
| Facebook Cover | ~2.7:1 | 820×312 |
| LinkedIn Cover | ~4:1 | 1584×396 |
How to Resize Without Distortion
To scale any image proportionally, multiply both dimensions by the same factor. If you only know the target width:
New Height = New Width × (Original Height ÷ Original Width)
Example: a 1920×1080 frame resized to 800px wide → 800 × (1080 ÷ 1920) = 450px. The 16:9 ratio holds. The “New Width” field in the calculator above does this automatically.
Why Aspect Ratio Matters
A ratio mismatch wastes screen space or distorts content. A 4:3 video on a 16:9 monitor gets vertical black bars (pillarboxing); a 16:9 video on a 4:3 screen gets horizontal bars (letterboxing). For print, DSLR cameras shoot at 3:2, but a standard 4×6 print is not exactly 3:2 — labs crop the edges unless you adjust first.
In web development, the CSS aspect-ratio property reserves the correct layout space as images load, preventing cumulative layout shift (CLS).
Frequently Asked Questions
What is the most common aspect ratio today?
16:9 is dominant: TVs, monitors, YouTube, and most phones in landscape mode. For vertical mobile content (TikTok, Reels), 9:16 is the standard. Ultrawide 21:9 is growing in gaming monitors.
How do I maintain aspect ratio when resizing?
Multiply or divide both width and height by the same factor. Use the calculator above — enter original dimensions and a new width, and it outputs the correct height automatically.
What aspect ratio should I use for social media?
Instagram feed: 1:1 or 4:5. Instagram/TikTok Reels: 9:16. YouTube: 16:9. Twitter/X header: 3:1. Facebook cover: ~2.7:1. LinkedIn cover: ~4:1.
What is the difference between 16:9 and 16:10?
16:9 (≈1.78) is the video and TV standard. 16:10 (1.60) provides slightly more vertical space, used on some laptops and older MacBook models. The extra height is useful for reading documents and reviewing code.
How do I find the aspect ratio of an image?
Enter the image width and height into the calculator above. To calculate manually: divide both values by their GCD. For 1920×1080 — GCD is 120, so 1920÷120 : 1080÷120 = 16:9.