About · Methodology · Operator

Last updated 2026-07-11

What this tool is

The Aspect Ratio Calculator (aspectcalc) is a free tool that locks a width:height ratio and derives the missing pixel dimension from a single input. It reduces any resolution to its lowest-terms ratio with the GCD, detects the nearest standard ratio, and fills exact platform sizes for Instagram, Reels, Shorts, YouTube, and more with one click. No signup — every calculation runs in your browser.

Methodology

• Solving: height = width × ratioHeight ÷ ratioWidth (or the reverse). Pure arithmetic, no external API.
• Reduction: the Euclidean algorithm computes the GCD to reduce an integer ratio to lowest terms.
• Nearest ratio: the standard preset with the smallest decimal-ratio distance is chosen, and marked an exact match within a 0.5% relative tolerance.
• Even rounding: 2 × round(value ÷ 2), because 4:2:0 codecs such as H.264 prefer even dimensions.

Data sources

• Standard ratios (16:9, 4:5, 21:9, …) are the common conventions of the broadcast, video, and display industries.
• Platform preset pixel sizes (Instagram, YouTube, TikTok, X, Facebook, LinkedIn, Naver) summarize each service's published recommendations and are updated when policies change.
• The even-dimension recommendation is based on the 4:2:0 chroma subsampling of H.264/H.265 codecs.

Privacy

Inputs are never sent to a server; they live only in your browser (localStorage) and the optional ?s= share token. No image or video file is uploaded, and there is no signup or tracking cookie — only advertising and traffic analytics needed to run the site.

Operator & disclaimer

• Operated by: bal.pe.kr (an independently run micro-SaaS portfolio)
• Contact: comsamo84@gmail.com
• More tools: bal.pe.kr tools

Platform specs are reference values that can change with each service's policy. This tool computes and displays pixel dimensions only; it does not resize or crop actual images or video.