Printable Ruler and Protractor

A printable ruler is something people look for at the moment they need one and do not have one, and most of what turns up is a picture that prints at whatever size the dialogue felt like. A ruler four per cent short is worse than no ruler, because you trust it. This is drawn in millimetres so it prints at true size, and the marks are measured off the finished drawing rather than merely intended.

What to print

Page size

Landscape, for the longest ruler the page will hold

Print at 100%.If the print dialogue says “fit to page” or “shrink to fit”, turn it off — otherwise the marks come out the wrong distance apart and the ruler lies to you.

✓ Every tick is the same distance from the next — 278 ticks, evenly spaced to within a hundredth
✓ Every number sits where that measurement really falls — 28 numbered marks, each within a hundredth of a millimetre of its true position
✓ The ruler is as long as the page allows — 277mm long, which is 27.7 cm
✓ It prints at the size it says — measured in millimetres, so printing at 100% gives a true ruler — anything else does not

What this generator does

Draws every tick at its exact position in millimetres, numbers the major ones, and writes the whole thing as an SVG with a millimetre viewBox so it prints life size.

How to use this tool

Choose a ruler, a protractor, or a conversion scale.
Pick the page size, and landscape for the longest ruler it will hold.
Download the SVG.
Print at 100% — not scaled to fit — and check a known length before you trust it.

Understanding the controls

What to print: A centimetre ruler down to single millimetres, an inch ruler down to sixteenths, a half-circle protractor marked every degree, or a two-sided conversion scale for temperature, distance or weight.
Page size: A4, A3, A5, US Letter or US Legal. A longer page gives a longer ruler, since the ruler runs the full width between the margins.
Landscape: Turns the page on its side, which is how you get the longest ruler a given sheet will hold — 277mm on A4 rather than 190.

Common use cases

Measuring something when the tape measure has gone missing
A protractor for homework the night before it is due
Handing a class a ruler each without buying thirty
A quick conversion scale to keep by the oven or in a map case
Checking a printer really is printing at true size

How this generator works

Everything is positioned in millimetres and the drawing carries a millimetre viewBox, so a printer at 100% produces the real thing. The check then measures what was drawn: consecutive ticks must be the same distance apart to within a hundredth of a millimetre, and every numbered mark must sit where its value says — a centimetre mark at exactly ten millimetres times its number, an inch mark at exactly 25.4. A conversion scale is checked differently and more strictly: each mark on the second scale is placed by converting its value into the first unit and marking it there, so the point labelled 60 miles is the same point as the one labelled 96.6 kilometres. Fahrenheit's low marks fall below the start of the Celsius scale, so they are left off rather than drawn into the margin.

Randomness and fairness

Nothing is random. The same settings always draw exactly the same instrument.

For how randomness is produced across the whole site, see how Generate Random works.

Limitations and good to know

Printing scaled to fit destroys the whole point; check a known length before trusting it.
Paper stretches slightly with humidity, so a paper ruler is good to about half a millimetre, not to a tenth.
The protractor is a half circle, not a full one, and has no bevelled edge to line up with.
A conversion scale is read to the nearest mark; it is a rough reckoner, not a calculator.

Privacy and your data

The drawing is made in your browser from fixed numbers. Nothing is uploaded, and no settings are stored.