CAD Tools · ScaleMate

Drawing Scale Calculator

Convert real dimensions to paper dimensions at any drawing scale — and back again. Metric, architectural and engineering scales.

Scale Converter

Type on either side — the other updates.

Drawing scale

Decimal places

Real size

On the drawing

Convert a list of dimensions

Real sizes — one per line

Optional label before a comma. Uses the real-size unit above.

On the drawing

Item	Real	Drawing

Scale Finder

Find the largest standard scale that fits your object on a sheet.

Object width

Object height

Unit

Scale type

Sheet

Margin each side

Allow for borders and the title block.

Recommended scale –

Scale	Size on drawing	Fits?

Printed at a Different Size?

Work out the true scale of a drawing printed smaller or larger than its sheet.

Scale on the drawing

e.g. 1:100, 100, or 2:1

Drawn for sheet

Printed on

True scale of the print –

Drawing Scale Guide

How scales work and which ones are used where.

Reading a Scale

1 : 100

1 unit on the drawing equals 100 of the same unit in reality — 1 mm on paper is 100 mm (0.1 m) real.

Real → Drawing

drawing = real ÷ 100

Divide the real size by the scale factor. A 5 m wall at 1:100 is 50 mm on the drawing.

Drawing → Real

real = drawing × 100

Multiply what you measure on the drawing by the scale factor to get the real size.

Enlargements

2 : 1 · 5 : 1 · 10 : 1

Small parts are drawn bigger than life. At 2:1, a 10 mm part is 20 mm on the drawing.

Common Metric Scales

1:5 · 1:20 · 1:50 · 1:100 · 1:500

1:1–1:10 for parts and details, 1:20–1:50 for rooms and sections, 1:100–1:200 for building plans, 1:500+ for sites.

Architectural (Imperial)

1/4" = 1'-0" → 1:48

Inches on paper per foot of building. Type feet and inches like 12' 6 1/2" in the real-size box.

Engineering (Imperial)

1" = 20' → 1:240

Inches on paper per tens of feet. Used for civil and site plans.

A-Series Prints

A1 → A3 = 50%

Each A size is half the area of the one above. An A1 drawing at 1:100 printed on A3 is 1:200. Add a scale bar so prints stay measurable.

Why ScaleMate?

ScaleMate is a fast, lightweight calculator for drafters, CAD designers, architects and engineers who need to move between real dimensions and drawing dimensions without reaching for a scale ruler.

All processing happens entirely in your browser. Nothing leaves your device.

100% Private — nothing is sent to a server

Both directions — real to drawing, drawing to real

Metric & imperial — including feet-and-inches input

Scale finder — the right scale for A0–A4 and ANSI sheets

Print scale — true scale of reduced prints