Free tool · runs in your browser
Architectural & Engineering Scale Calculator
Convert between paper measurements and real-world dimensions at any architectural or engineering scale — 1/4"=1'-0", 1/8", 1:50, 1:100, and more. Free, in your browser.
No signup · nothing uploaded · Free — unlimited use, runs entirely in your browser
How it works
Choose the drawing scale
Pick from standard architectural and metric scales.
Enter a measurement
A paper measurement (in or mm) or a real size (ft/in).
Read the conversion
The real-world equivalent — or the paper length — instantly.
Pick a drawing scale and convert in both directions: a measurement taken off the printed sheet becomes the real-world size, or a real dimension becomes the length it should measure on paper. Covers the standard imperial scales (1/16" through 3" = 1'-0") and metric ratios (1:1 through 1:500).
This is the same math the PDFDepth workspace applies when you calibrate a sheet — except there you click two points on the drawing itself and every measurement that follows comes out in real units automatically.
Questions, answered
Multiply the paper measurement in inches by 48 — that is the ratio (1/4 inch represents 12 inches, so 12 ÷ 0.25 = 48). At 1/4" scale, 1 paper inch = 4 real feet. The calculator does this for every standard scale.
More free tools
Need more than the free limit?
In PDFDepth you calibrate the sheet once and every length, area, and count you measure comes out in real units — no manual conversion.
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