Why the 12-inch ruler comes in two pieces
A 12-inch ruler is longer than a Letter (8.5 × 11 in) or A4 page is wide, and printers cannot print right to the edge. So the ruler is split into two 6-inch pieces. Piece 2 has a shaded glue tab. Slide it under the end of piece 1 so the 6-inch marks meet exactly, then glue or tape it. If you have US Legal (8.5 × 14 in) or A3 paper, the ruler pack prints a one-piece 12-inch 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 inch fractions
Each inch is divided into 16 parts. The tallest line between two numbers is 1/2", the next tallest are the quarters (1/4", 3/4"), then the eighths and finally the shortest lines, the sixteenths. To read a measurement, count whole inches, then count sixteenths past the last number and simplify. For example, 6/16 is 3/8.
| Mark | Inches | Millimetres |
|---|---|---|
| 1/16" | 0.0625 | 1.59 |
| 1/8" | 0.1250 | 3.17 |
| 3/16" | 0.1875 | 4.76 |
| 1/4" | 0.2500 | 6.35 |
| 5/16" | 0.3125 | 7.94 |
| 3/8" | 0.3750 | 9.52 |
| 7/16" | 0.4375 | 11.11 |
| 1/2" | 0.5000 | 12.70 |
| 5/8" | 0.6250 | 15.88 |
| 3/4" | 0.7500 | 19.05 |
| 7/8" | 0.8750 | 22.22 |
| 1" | 1.0000 | 25.40 |
Which ruler on the sheet to use
- 1/16" ruler. This is the everyday standard for woodworking, home projects and school.
- 1/32" precision ruler. Use it for fine work such as model making, bookbinding or checking thicknesses.
- 1/10" decimal-inch ruler. Engineers and machinists use it, and it is handy when a spec says 2.35" rather than 2 3/8".
Need to convert a reading? Use the inch fraction to cm converter.
Frequently asked questions
How do I join the two pieces accurately?
Cut both pieces along their solid outlines. Lay piece 1 face up, slide the glue tab of piece 2 underneath so the edge of piece 2 butts against the end of piece 1, and check that the inch marks run on evenly. Then tape or glue the joint.
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.
Is 12 inches the same as 30 cm?
Not quite. 12 inches is 30.48 cm. A 30 cm ruler is about 5 mm shorter than a 12-inch ruler.
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.