Free Printable Ruler (Actual Size PDF)
Quick answer: Print this ruler at 100% scale (turn off 'fit to page') on Letter or A4 paper for an accurate, actual-size ruler in inches and centimeters.
Need a ruler right now? Download and print this free PDF ruler: a 9-inch imperial ruler with 1/16" divisions and a 22 cm metric ruler with millimeter marks — plus a built-in calibration square so you can verify your print is true to scale.
Letter size · print at 100% / "Actual size" · no signup required.
How to print it accurately
- Open the PDF and choose Print.
- Set scale to 100% or select "Actual size" — never "Fit to page", which shrinks the ruler by 3–6%.
- Print on plain letter paper. Heavier paper (24–32 lb) stays flatter and is easier to use.
- Verify: measure the 1-inch check square and 5 cm check bar on the printout. If they match, every marking on the ruler is accurate.
- Cut along the ruler edge with scissors or a utility knife.
What’s on the ruler
| Ruler | Length | Smallest division |
|---|---|---|
| Imperial | 9 inches | 1/16 inch |
| Metric | 22 centimeters | 1 millimeter |
Measuring something longer? Mark where the ruler ends, slide it so zero meets your mark, and keep a running total.
Why printed rulers come out wrong
Nearly every scaling error traces back to one setting. Print dialogs default to "Fit to page" or "Shrink oversized pages", which silently reduces the document by 3–6% so nothing clips at the margins. On a text document that is invisible. On a ruler it makes every measurement wrong by the same proportion — and consistently wrong, which is worse than obviously wrong, because you will not notice.
Set scaling to 100%, Actual size, or None depending on your print dialog, then verify against something of known length before you trust it. A US letter sheet is exactly 8.5 in wide; A4 is exactly 210 mm. A credit card is 85.6 × 53.98 mm worldwide, which makes it a reliable check object that is always to hand.
Paper size matters more than you would expect
A PDF laid out for US Letter printed on A4 (or the reverse) will be rescaled by the driver to fit, because the two sizes are not proportional — A4 is narrower and taller. That rescaling reintroduces exactly the error you were trying to avoid. Print the version matching the paper actually in your tray, and turn off any "auto-rotate and centre" option that might shift the layout.
When a printed ruler is genuinely useful — and when it is not
A printed ruler is a good stand-in for quick, low-consequence measuring: checking a screw length, sizing a photo, confirming a bolt diameter, teaching fractions, or measuring something small when your tape is in the truck. Glue it to card stock or laminate it and it will survive a workshop drawer.
It is a poor choice for anything cumulative or structural. Paper stretches with humidity, printers drift, and errors compound over distance — a 1% error over 6 inches is negligible, but carried across a 16 ft wall it becomes nearly two inches. For layout, framing, cutting stock, or anything where several measurements add together, use a steel tape or rule.
Fractions, decimals, and metric
| Fraction | Decimal inch | Millimetres |
|---|---|---|
| 1/16 | 0.0625 | 1.59 |
| 1/8 | 0.125 | 3.18 |
| 1/4 | 0.25 | 6.35 |
| 3/8 | 0.375 | 9.53 |
| 1/2 | 0.5 | 12.7 |
| 5/8 | 0.625 | 15.88 |
| 3/4 | 0.75 | 19.05 |
| 7/8 | 0.875 | 22.23 |
| 1 | 1.0 | 25.4 |
Frequently asked questions
How do I print a ruler in actual size?
Set your printer scale to 100% (or "Actual size") and disable "Fit to page". Then check the calibration square: if it measures exactly 1 inch, the ruler is true.
Is a printed ruler accurate?
Printed at 100%, yes — accurate to a fraction of a millimeter, which is plenty for woodworking layout, sewing, picture framing, and school work. Verify with the check square before critical measurements.
Can I laminate it?
Yes. Lamination adds a hair of thickness at the edge but doesn’t change the scale. It makes the ruler far more durable.