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Printable Ruler

Calibrate your screen against a real card, then generate a centimetre or inch ruler with 1/8, 1/16 or 1/32 subdivisions that is accurate when printed at 100%.

Step 1 — calibrate this screen

Hold a bank card (or any object you know the size of) against the line below. Adjust the slider until the line is exactly as long as the card, then apply it.

The line above is 324 screen pixels wide. If your card is longer than the line, raise the scale; if shorter, lower it.

ISO/IEC 7810 ID-1 — credit, debit and most ID cards: 85.60 mm

Not calibrated yet — the slider uses your display's reported scale, which is often close but rarely exact.

Step 2 — print or download

A4 · 210 × 297 mm · portrait · 150 DPI

Print-at-100% instructions

  1. Choose Print, then set Scale / “Fit to page” to 100% (never “Fit”).
  2. Turn off “Shrink to fit” or “Scale to fit paper” in your printer driver.
  3. Print on A4 · 210 × 297 mm at portrait orientation.
  4. Measure the red test line above the scale — it must be exactly 100 mm. If it is not, fix the scale and reprint.

Ruler

Unit
Inch subdivisions

Paper

Size
Orientation

Landscape gives you a longer single ruler: A4 landscape fits 28 cm, Letter landscape 27 cm.

About this tool

A printed ruler is only trustworthy when the geometry is right, so this tool separates the two problems: the on-screen reference line is calibrated against a bank card, coin or real ruler (ISO/IEC 7810 ID-1 is 85.60 mm), while the printable sheet is drawn directly in millimetres at 150 DPI on A4 (210 × 297 mm) or US Letter (8.5 × 11 in) — so printing at 100% gives true centimetres and 1/8, 1/16 or 1/32 inch subdivisions, with a 100 mm verification line to prove it. Calibration, drawing and export all run locally in your browser.

  • 100% free — no account needed
  • Runs in your browser
  • Nothing is uploaded

Frequently asked questions

Is Printable Ruler really free?

Yes. Printable Ruler is completely free on PureBrowser — every feature, with no account, no trial, and no credit card.

Does Printable Ruler upload my data?

No. Printable Ruler runs entirely inside your browser, so anything you type, paste, or open stays on your own device.

Do I need to sign up or install anything?

Neither. There is no account and nothing to download — open the page and Printable Ruler is ready to use on desktop or mobile.

Does Printable Ruler work offline?

Once the page has loaded, yes. All of the processing happens locally in your browser, so it keeps working without a connection.

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