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Printable Ruler — Free PDF in Inches and Centimeters

A 12-inch ruler, a 7-inch ruler and a 30 cm ruler at actual size, for US Letter or A4 paper.

Download US Letter PDF8.5 × 11 in · US, Canada, MexicoDownload A4 PDF210 × 297 mm · rest of the world

Print at 100% (“Actual size”). Then check the square on the page with a real ruler or a coin before you measure.

Preview of the printable ruler: 12-inch ruler in two parts, a 7-inch ruler and a 1-inch check square
Detecting device...
About·Contact
Printable ruler

How to print a ruler at actual size

Printers often shrink pages to fit the paper, which makes a printed ruler too small. These PDFs are drawn at exact size, and each page has a check square so you can confirm the printout is right before you measure.

Related guides: How to Read a Ruler (Inches and Centimeters) · How to Read a Tape Measure

How to use it

  1. Download the PDF for your paper: US Letter in the US, Canada and Mexico, A4 elsewhere.
  2. In the print window, set scale to 100% or Actual size. Turn off “Fit to page” and “Shrink to fit”.
  3. Check the square: it should measure exactly 1 inch (or 2 cm). For the 12-inch ruler, cut out both parts and tape them where the 6s line up.

Good to know

  • Page 1 has inch rulers marked to 1/16 inch; page 2 has centimeter rulers marked every millimeter.
  • Printing on card stock or thick paper gives a stiffer ruler that lasts longer.
  • No printer at hand? The on-screen ruler above works at actual size after calibration.
Guide

Three ways to calibrate

1

Auto-detect your device

The ruler recognizes about 130 phones, tablets, laptops and monitors, including iPhones, Galaxy phones, Pixels and MacBooks.

Instant±1%
2

Enter your screen size

Enter your screen's diagonal size (for example, 15.6" for a laptop), and the ruler works out the scale from your screen resolution.

Manual±2%
3

Calibrate with a bank card

Hold any bank card against the outline on screen and move the slider until they match. Bank cards are the same size everywhere: 85.60 × 53.98 mm.

Most Accurate±0.5%
Accuracy

How accurate is the ruler?

How accurate the ruler is depends on how well it knows your screen's pixel density, meaning how many pixels fit in an inch. There are three ways to set it, from most to least accurate:

Bank card (±0.5%): Bank and credit cards are made to one worldwide size, 85.60 × 53.98 mm (ISO/IEC 7810 ID-1). Because every card is exactly the same, matching one on screen gives the most accurate result.

Auto-detect (±1%): The ruler looks up your device's published screen size and resolution. Screens of the same model can differ very slightly, so this is a little less exact. It covers about 130 devices.

Screen size (±2%): You type in your screen size, and the ruler works out the rest from your resolution. Advertised sizes are rounded (a "15.6-inch" screen may really be 15.59 inches), so this is the least exact method. It's a good fallback when you don't have a card.

Reference Sizes

Real-life objects to check your measurements

Use these everyday objects to confirm the ruler is calibrated correctly.

Bank or credit card: 85.60 × 53.98 mm (3.37 × 2.13 in)

A4 paper: 210 × 297 mm (8.27 × 11.69 in)

US Letter paper: 8.5 × 11 in (215.9 × 279.4 mm)

US quarter: 24.26 mm (0.955 in) across

1 euro coin: 23.25 mm (0.915 in) across

AA battery: about 50.5 mm long and 14.5 mm wide

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FAQ

Frequently asked questions

Your print settings scaled the page. Print again with scale set to 100% or “Actual size”, and turn off “Fit to page”, “Shrink oversized pages” and any borderless printing. Then check the 1-inch square with a real ruler or a US quarter (0.955 inches across).

US Letter paper is 11 inches long, so a 12-inch ruler can't fit in one piece with printer margins. The PDF splits it into two parts (0–6 and 6–12) that you cut out and tape together, with a grey tab to line up the 6s.

Use US Letter in the US, Canada and Mexico, and A4 almost everywhere else. Both PDFs contain the same rulers; only the page size differs, so the rulers are the same size either way.

When printed at 100%, most printers are accurate to within about 1%. Always measure the check square first. For small parts, the calibrated on-screen mm ruler can be more precise.