---
title: "Printable Scale Ruler: HO, N, OO, O, 1:35 | Diorama Fern"
description: "Print a scale ruler marked in real metres and feet for HO, N, OO, O, 1:35, 1:72 or any 1:N scale, with a calibration bar to check it printed at 100%."
url: https://dioramafern.me/scale-ruler/
---

Real metres · real feet · any 1:N

# Printable scale ruler

Measure a model or a plan in real-world units. Pick a scale, print at 100%, and check it against the calibration bar.

## How to print it at the right size

1. Choose your scale, or type any ratio. The ruler is marked in real-world units, so at HO each numbered step is one real metre (11.48 mm on paper) or five real feet.
2. Press **Print ruler**. In the print dialog set the scale to **100%** or **Actual size**, and turn off “Fit to page” or “Shrink to fit”. Only the ruler sheet prints.
3. Measure the calibration bar with an ordinary ruler: the top bar must be exactly 100 mm and the bottom one exactly 4 in. If it is off, the printer has scaled the page; fix the setting and print again.
4. Cut along the outline and glue it to card or plastic strip, or keep the SVG and print it again whenever you need one.

The numbers sit on the round real distances that stay readable on paper: tick spacing never drops below 1 mm, and numbered steps are at least 8 mm apart, so small scales such as N and Z are numbered every 2 m. Ratios come from the NMRA and NEM standards for railway scales, and kit and dollhouse scales follow common conventions.

**Free printable kits and textures?** Paper building kits, card models and texture sheets are often given away in exchange for an email address. A temporary inbox from [CleanTempMail](https://cleantempmail.com/) (no sign-up, emptied after three days) receives the download link without the newsletters that follow. Download the files straight away, because the inbox will not keep them, and use your real address for kit orders.

## Questions

**Why does my printed ruler come out the wrong size?**

Most print dialogs shrink pages to fit the printable area unless told not to. Set the scale to 100% or Actual size and print again, then check the 100 mm calibration bar with a real ruler.

**Can I make a ruler for a scale that is not in the list?**

Yes. Type any ratio from 1:1 to 1:10,000 in the ratio box, such as 1:87.1, 1:25 or 1:300, and the ruler and its tick spacing follow.

**What do the small ticks stand for?**

Each strip says so in its bottom corner. They split each numbered step as finely as possible while staying at least 1 mm apart on paper: 10 cm at HO on the metric side and 6 in on the imperial side.

## Sources

- Railway scale ratios: [NMRA S-3.2, Track, Standard Scale](https://www.nmra.org/sites/default/files/standards/sandrp/Mech/S/s-3.2_track_standard_scale.pdf) (2026) and [MOROP NEM 010, Scales, Nominal Sizes, Gauges](https://www.morop.org/images/NEM_register/NEM_E/nem010_en_2011.pdf) (2011). Kit, figure and dollhouse scales and their sources are listed on the [scale converter](https://dioramafern.me/#sources).
- Inch (25.4 mm) and foot (0.3048 m): [NIST Handbook 44](https://www.nist.gov/pml/owm/nist-handbook-44-current-edition), Appendix C.