---
title: "Printable ruler and scale check — free, runs in your browser"
description: "Print an accurate ruler in centimetres or inches, with a calibration check. Free, no sign-up, and nothing you enter leaves your browser."
url: https://atoneplace.net/tools/printable-ruler/
site: "At One Place"
---

# Printable ruler and scale check

Print an accurate ruler in centimetres or inches, with a calibration check.

## How it works

Generates a printable ruler in centimetres, inches or both, with a calibration rectangle to confirm your printer produced it at true size.

Print scaling is the reason most printable rulers are wrong. Print dialogs default to shrinking slightly — "fit to page" or "shrink oversized pages" — to accommodate unprintable margins, and a ruler printed that way is typically 2 to 4% short. Over 30 cm that is nearly a centimetre of error, which is worse than useless.

The calibration rectangle is exactly 100 mm wide. Measure it against a known ruler or a bank card, which is 85.60 mm wide by the ISO/IEC 7810 ID-1 standard and is the most reliably sized object most people have. If the rectangle is not 100 mm, print scaling was applied.

Output is SVG in millimetre units, which is what allows true-size printing independent of printer resolution.

> This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

## Common questions

### Why is my printed ruler the wrong size?

Print scaling. Dialogs default to shrinking a few per cent to fit unprintable margins. Set scale to 100% and turn off "fit to page".

### How can I check the scale without a ruler?

A bank card is 85.60 mm wide by ISO/IEC 7810 — the most reliably sized object most people own. Measure the calibration rectangle against it.

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## Sources

- Calculated on this page — At One Place (/about/)