PhotoCalcs
Video Aspect Ratio Calculator — Dimensions
Calculate video dimensions for common aspect ratios with pixel-perfect even numbers.
How We Calculate This
Height Calculation
Height = width ÷ (ratio width ÷ ratio height)
The height is rounded to the nearest whole pixel, then rounded up to the nearest multiple of your Pixel Alignment (default 2) so the dimensions stay codec-friendly. For example, 16:9 at 3840px wide gives 3840 ÷ (16÷9) = 2160px, which is already even — exactly 4K UHD.
Frequently Asked Questions
16:9 is the standard for HD and 4K content. Cinema uses wider ratios: 1.85:1 (Flat) and 2.39:1 (Scope, the modern anamorphic standard since SMPTE’s 1970 aperture revision — older films use the legacy 2.35:1). Social media uses 1:1 (square), 4:5 (portrait), and 9:16 (vertical stories/reels). Choose based on your delivery platform.
Most video codecs (H.264, H.265, ProRes) process pixels in blocks of 2x2 or larger. Odd dimensions cause encoding errors or padding issues. Video editors and export tools automatically enforce even dimensions.
4K UHD is 3840x2160 (16:9). DCI 4K (cinema) is 4096x2160 (slightly wider than 16:9). 4K has 4x the pixels of 1080p. 8K UHD is 7680x4320. Many cameras offer DCI 4K for the wider frame.
To create 2.39:1 (Scope) from 16:9 footage, add black bars top and bottom. For a 3840x2160 source: 2.39:1 active height = 3840/2.39 = 1607px. Bars = (2160-1607)/2 = 276px (top and bottom). This is called letterboxing. Some filmmakers shoot 16:9 and crop in post for the cinema look.
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Last updated: February 2026
All calculations are estimates based on standard optical and photographic formulas. Results may vary with specific equipment.