Aspect Ratio Calculator Free Online
Calculate aspect ratios and scale dimensions. Enter any two of width, height, or ratio and the tool computes the rest. Recognizes common ratios (16:9, 4:3, 21:9, 1:1, 9:16) for video, photo, and social media.
Edit any field — the others recompute. Edit Width to find Height; edit Ratio to rescale both dimensions.
Pro — bulk batch conversion, API access, history & favorites
API access · Priority queue · Team workspace
Related Tools
How It Works
Pick Your Unit or Preset
Choose your home unit using the dropdown or load a one-click preset. Defaults are sensible engineering values so you can start right away.
Enter a Value
Type a number — conversion runs as you type. Many tools have multiple input boxes (W & H, size & speed) — edit any of them and the rest recompute.
Read Every Equivalent
Below the main result, the All Units / Summary panel shows your value across every supported unit, with engineering context (FPS, ping, EM band, etc.) where relevant.
Aspect Ratio Calculator Features
Solve Any Side
Edit width and height auto-fills based on the ratio. Edit ratio and height re-scales. Three-variable solver.
12 Presets
One-click load for 16:9, 9:16, 4:3, 3:2, 1:1, 21:9, 2.39:1, 5:4, 16:10, 2:3, 4:5 — covers TV, cinema, social media, and photography.
Photo Standards
3:2 (DSLR / mirrorless), 4:3 (phone / Micro Four Thirds), 4:5 (Instagram portrait).
Video Standards
16:9 (FHD / 4K), 9:16 (TikTok / Reels), 21:9 (ultrawide), 2.39:1 (Hollywood anamorphic).
Live Calculation
Updates as you type — no Calculate button.
100% Private
All math runs in your browser.
Free vs Pro
| Feature | Free | Pro |
|---|---|---|
| Full aspect ratio conversion | ||
| Live conversion | ||
| All-units result panel | ||
| Bulk CSV / Excel conversion | — | |
| REST API access | — | |
| Custom precision settings | — |
Frequently Asked Questions
16:9 — used for almost every modern TV, monitor, smartphone (landscape), and YouTube video. Decimal: 1.7778. The vertical version (9:16) dominates short-form video like TikTok and Reels.
Most modern movies are 2.39:1 (anamorphic widescreen) or 1.85:1 (academy widescreen). When you watch on a 16:9 TV you get black bars top and bottom. IMAX is closer to 1.43:1.
Multiply width by 9/16. So 1920 × 9 / 16 = 1080. The tool does this automatically — just enter the width and the height appears.
4:5 (1080 × 1350) is the tallest portrait that still fits in the feed without being cropped. 9:16 (full vertical) gets cropped on the feed but works for Stories and Reels.
16:9 is 1.778 (TV / phones); 16:10 is 1.6 (older laptops, MacBook Pro 16"). The 16:10 panel is taller, giving more vertical space for documents and code.