About this tool
What is the Aspect Ratio Calculator?
Enter any width or height and the calculator returns the matching dimension to preserve the aspect ratio. Pick a preset (16:9 HD, 9:16 vertical, 1:1 square, 2.39:1 cinemascope, 21:9 ultrawide) or enter a custom ratio.
Filmmakers use it for figuring out canvas dimensions for AI image generation (e.g., 'I need 2.39:1 at 2048px wide — what's the height?'). Designers use it for resizing assets without distortion.
FAQ · ASPECT RATIO CALCULATOR
Questions about the Aspect Ratio Calculator
What aspect ratios are pre-configured?
16:9 (HD/4K video), 9:16 (Instagram Reels, TikTok), 1:1 (Instagram square), 4:5 (Instagram portrait), 2.39:1 (cinemascope), 1.85:1 (theatrical wide), 21:9 (ultrawide), 3:2 (DSLR photo), 2:3 (portrait DSLR). Plus a custom field for any ratio.
Can I use it for AI image generation dimensions?
Yes — that's a common use. Enter your target wide-side resolution and the calculator gives the exact other side. Most AI image models prefer dimensions that are multiples of 8 or 64; the tool snaps to those if you enable it.
Free?
Yes — no signup, runs in-browser.