Ratio Calculator

Simplify a ratio, and see it as shares of the whole.

Written and maintained by Mohit PatelLast checked August 4, 2026How we build these

First part

Second part

Third part

Optional.

Simplified ratio

2 : 3

As a decimal, 0.666667 : 1

Original12 : 18

Simplified2 : 3

As a decimal0.666667 : 1

Part 1 share40.00%

Part 2 share60.00%

Total30

Simplifying divides every part by their greatest common factor, which changes how the ratio is written without changing what it means. The percentages are the same information expressed against the whole rather than against each other — useful when the parts are being shared out rather than compared.

How the Ratio Calculator works

Simplifying divides every part by their greatest common factor, which changes how a ratio is written without changing what it means. The percentages alongside are the same information measured against the whole rather than against each other — the form you want when the parts are being shared out.

Also known as: simplify a ratio · ratio to percentage calculator · ratio to fraction converter · how to simplify a ratio

Where to go next

The Ratio question rarely arrives on its own. These are the ones that usually come with it:

Proportion Calculator — Solve a : b = c : d for whichever term is missing.
GCF Calculator — Greatest common factor, with every common factor listed.
Percentage Change Calculator — Change, and the reverse move needed to undo it.
Percentage Calculator — Every common percentage question in one place.

Sources

NIST Digital Library of Mathematical Functions

Frequently asked questions

How do I simplify a ratio?

Divide every part by their greatest common factor. 12 : 18 has a GCF of 6, so it simplifies to 2 : 3.

How do I turn a ratio into a percentage?

Divide each part by the total. In 12 : 18 the total is 30, so the parts are 40% and 60%.

Can a ratio have decimals?

Yes, and this scales them to whole numbers first — 2.5 : 5 simplifies to 1 : 2 rather than staying in decimal form.

What is the difference between a ratio and a fraction?

A ratio compares parts to each other; a fraction compares a part to the whole. In 2 : 3, the first part is two thirds of the second but two fifths of the total.

Put this calculator on your own site

Free to use, on any site, commercial or not. Paste this where you want it to appear. It is a plain iframe, so it works in WordPress, Squarespace, Wix, Webflow, Ghost and anything else that accepts HTML.

The one-line version

<iframe src="https://www.thecalclibrary.com/embed/ratio-calculator" width="100%" height="640" style="border:1px solid #e2e8f0;border-radius:12px" loading="lazy" title="Ratio Calculator"></iframe>
<p style="font:13px/1.5 system-ui,sans-serif;margin:6px 0 0;color:#64748b">Powered by <a href="https://www.thecalclibrary.com/ratio-calculator" style="color:#64748b">Ratio Calculator</a> from The Calc Library</p>

The only condition is that the credit line below the frame stays in place. That one line is what pays for the tool being free — it is how anyone else finds it.