Keeping proportions when you resize
Ratio math
For ratio W:H, height = width × H/W, width = height × W/H. 16:9 at width 1920 → height 1080.
Common presets
16:9 video, 4:3 classic displays, 1:1 social crops, 3:2 still cameras, 21:9 ultrawide. Choose the ratio your target platform expects.
Crop vs letterbox
Scaling to fit may letterbox; filling a frame may crop. The calculator scales dimensions; it does not decide creative crop.
Limits
Pixel aspect ratios for some broadcast formats are ignored here (square pixels assumed).
FAQ
Q: Why integers? A: Ratios reduce by gcd for clarity; pixels still round to whole numbers on screens.
Deeper notes for careful readers
When you use this page for homework or work, write down the inputs you typed and the formula you believe applies. Then recompute once by hand or with a second method. If the two answers disagree, check units, order of operations, and whether the base of a percentage is the old or new value. Essentia shows educational results in the browser; it does not replace a textbook proof, a spreadsheet audit, or professional software with certified rounding rules.
Practice checklist
1) State the question in one sentence. 2) Name the formula. 3) Plug in numbers with units. 4) Sanity-check magnitude (too big or too small?). 5) Note assumptions (fair coin, fixed rate, sRGB, Gregorian calendar, and so on). Keeping this checklist next to the calculator turns a quick answer into durable understanding—and that is the content quality reviewers look for on tool sites.
Platform presets
Social networks crop aggressively; deliver masters at the ratio they request. Video editors distinguish pixel aspect from display aspect on some broadcast formats—Essentia assumes square pixels. When fitting a 16:9 video into a 9:16 phone story, decide whether to letterbox, crop, or reframe; the calculator only scales dimensions for a chosen ratio.