# Origami Paper Size Calculators & Unit Convertors

On this page you will find some very useful free online conversion tools. These include a paper size calculator, paper ratio convertor and a unit convertor.

These calculators and convertors are useful for those times when working things out yourself will take too long or you just don’t have a ruler, calculator or the time.

Origami models can of course be upscaled but what if there is a specific paper size used, such as B6 or A3? What if you don’t use cm and only use inches? What if the origami model needs two different sizes of paper and your paper is smaller?

Add a bookmark by holding down your CTRL (command on Mac) and tapping D.

## Unit Convertor

If you are in the US, you’re probably used to using inches, but for most of the world, millimetres and centimetres are the norm. Use the handy calculator below to convert between inch, mm and cm.

## A4 Paper Ratio Calculator

This simple calculator will work out the size you should trim your paper to if A4 size paper is required for the origami model.

For example, if you only have 20 x 20cm paper, you can work out that you’d need to trim it to 20 x 14 cm, by putting 20 into the “Long Edge” field.

This convertor works for all “A” sizes such as A2, A3 etc.

## Any Size Ratio Calculator

The below calculator will help you if you need a specific ratio of paper.

For example, if the origami model starts with paper that is 30 x 10cm, you can use this calculator to work out what size your smaller or larger paper should be.

This is very helpful for upscaling origami models.

## Paper Size Calculator

This calculator is helpful if you want to work out how big your paper needs to be to make an origami model a specific size.

For example, you would like a box that is 10 x 10cm when it’s completed. But the tutorial makes a box that is 15 x 15 cm. You can use the below calculator to work out the size of paper you will need.

## Origami Models Using 2 Sizes Of Paper

This calculator is for working out what size paper you need if you’d like to upscale or downscale an origami model, but two different sized papers are needed.

For example, a box and it’s lid. The box uses 10 x 10cm and the lid uses 12 x 12cm.

Notice anything interesting about these calculators? That’s right, all three of them use the exact same sum.
That sum goes:
x / y = z
a or b * z

## Useful Calculator

Here is a simple calculator that also has a memory of the sums to the right.

That’s it, we hope you find these online paper calculators useful.