One page with two workshop essentials: a true-size ruler (25 cm / 10 in) and the complete mm-to-inches fraction chart. Follow the print steps so it comes out at exact size.
Print it right — 3 settings that matter
Scale: 100% (or "Actual size"). Never "Fit to page" — that shrinks the ruler.
Check the test box: after printing, measure the blue box below with any ruler or card. It must be exactly 50 mm. If it is not, adjust your printer scale and print again.
Paper: A4 or Letter both work; card stock stays flat longer.
Accuracy test box — must measure 50 mm × 50 mm
50 mm
Centimetre ruler (0–25 cm)
Inch ruler (0–10 in)
MM to inches fraction chart
Millimetres
Centimetres
Inches (decimal)
Nearest 1/64 fraction
1 mm
0.1 cm
0.0394 in
≈ 3/64 in
2 mm
0.2 cm
0.0787 in
≈ 5/64 in
3 mm
0.3 cm
0.1181 in
≈ 1/8 in
4 mm
0.4 cm
0.1575 in
≈ 5/32 in
5 mm
0.5 cm
0.1969 in
≈ 13/64 in
6 mm
0.6 cm
0.2362 in
≈ 15/64 in
7 mm
0.7 cm
0.2756 in
≈ 9/32 in
8 mm
0.8 cm
0.3150 in
≈ 5/16 in
9 mm
0.9 cm
0.3543 in
≈ 23/64 in
10 mm
1 cm
0.3937 in
≈ 25/64 in
12 mm
1.2 cm
0.4724 in
≈ 15/32 in
15 mm
1.5 cm
0.5906 in
≈ 19/32 in
20 mm
2 cm
0.7874 in
≈ 25/32 in
25 mm
2.5 cm
0.9843 in
≈ 63/64 in
30 mm
3 cm
1.1811 in
≈ 1 3/16 in
40 mm
4 cm
1.5748 in
≈ 1 37/64 in
50 mm
5 cm
1.9685 in
≈ 1 31/32 in
75 mm
7.5 cm
2.9528 in
≈ 2 61/64 in
100 mm
10 cm
3.9370 in
≈ 3 15/16 in
Screen instead of paper?
If you would rather measure on screen, the online ruler shows the same scales at actual size after a quick bank-card calibration. And for conversions on the fly, the mm-to-inches converter gives decimal and fraction answers instantly.
Frequently asked questions
Why did my ruler print the wrong size?
Almost always the printer's "fit to page" or a scale other than 100%. Reprint with scale exactly 100% and verify with the 50 mm test box before measuring anything important.
Is a printed ruler accurate enough?
Yes for crafts, school and home sizing — within about half a millimetre over 25 cm when printed correctly. For engineering tolerances, use a metal ruler or caliper.
What does the fraction column mean?
Rulers and tape measures read in fractions (1/16, 1/32, 1/64), not decimals. The chart rounds each mm value to the nearest 64th so you can find it on a real ruler.