How to print the 30 cm ruler
An A4 sheet is 21 cm wide, so the 30 cm ruler prints as two 15 cm pieces. Piece 2 has a glue tab that slides under the end of piece 1, and the 15 cm marks meet at the joint. If you print on A3, choose the ruler pack for a one-piece 30 cm ruler.
- Pick the template and your paper size above. Letter is the US and Canada standard; most other countries use A4.
- Press Print, or Save PDF if you are printing from a phone or another computer.
- In the print window set Scale to 100% (Chrome, Edge, Firefox) or Actual size (Adobe Reader, macOS Preview). Turn off "Fit to page" and "Shrink oversized pages".
- Before cutting, lay a real ruler or a bank card on the scale-check bars. The 5 cm bar must be 5 cm and the 2 in bar 2 in.
Reading a metric ruler
Each numbered line is a centimetre, and each small line is a millimetre (10 per centimetre). The medium line halfway between numbers is 5 mm. A reading of 12 numbered lines plus 7 small lines is 12.7 cm, or 127 mm. The 150 mm ruler on the sheet is numbered in millimetres (10, 20, 30…). Engineers, 3D-printing hobbyists and anyone reading mm-based specs often find that easier.
| Metric | Inches | Nearest fraction |
|---|---|---|
| 1 cm | 0.394 | 3/8" |
| 2 cm | 0.787 | 13/16" |
| 5 cm | 1.969 | 1 15/16" |
| 10 cm | 3.937 | 3 15/16" |
| 15 cm | 5.906 | 5 7/8" |
| 20 cm | 7.874 | 7 7/8" |
| 25 cm | 9.843 | 9 13/16" |
| 30 cm | 11.811 | 11 13/16" |
Common uses
- Clothing sizesEU and Asian size charts are in centimetres.
- Paper and photo formatsCheck A-series sizes, photo prints and margins.
- School and lab workGeometry, physics experiments and graph drawing.
- HardwareScrew lengths, pipe diameters and 3D-printed parts in mm.
Frequently asked questions
Is this cm ruler accurate on A4?
Yes, when printed at 100% scale. Check the 5 cm bar at the bottom of the sheet against a real ruler, or lay a bank card on the outline. It should cover it exactly.
My printout is slightly too small. What went wrong?
Almost always the print window was set to "Fit to page", "Fit to printable area" or "Shrink oversized pages", which shrinks the page by 3–6%. Print again with Scale 100% or Actual size. See how to print at actual size for every browser.
How many centimetres are in an inch?
Exactly 2.54 cm (25.4 mm). The bottom edge of the 30 cm ruler is marked in inches so you can compare.
How accurate is a printed ruler?
The sheet is drawn in real millimetres and inches, so at 100% scale it is as accurate as your printer, which is typically within 0.5 mm over 30 cm. Every sheet has scale-check bars and most have a bank-card outline so you can confirm the size before you rely on it. For engineering or construction tolerances, use a certified steel rule.
Last reviewed 2026-10-07.