What does Contrast Ratio Calculator do?

Contrast Ratio Calculator is a free online tool from MarkVibe that lets you compute WCAG contrast ratio between two colors. No sign-up, no install — open the page and use it.

Is Contrast Ratio Calculator free?

Yes, Contrast Ratio Calculator is 100% free with no credit card, no daily limit, and no watermark. Use it as often as you like.

Does Contrast Ratio Calculator send my data to a server?

No. Contrast Ratio Calculator runs entirely in your browser using client-side JavaScript, so your input stays on your device.

Does Contrast Ratio Calculator work on mobile?

Yes. Contrast Ratio Calculator is fully responsive and works on any modern browser — Chrome, Firefox, Safari, Edge on phones, tablets, and desktops.

Where can I find more color tools?

MarkVibe ships 480+ free utilities including a full suite of color tools. Scroll to the Related tools section below to discover more in this category.

Contrast Ratio Calculator — Free Online Tool

What is the Contrast Ratio Calculator?

The Contrast Ratio Calculator is a free online color tools from Markvibe. Compute WCAG contrast ratio between two colors. It runs entirely in your browser — your data never gets uploaded — and works on desktop, tablet and mobile with no sign-up.

Reviewed by The Markvibe Team · Last updated 2026-06-28

Example

A worked example so you know exactly what to expect.

Input

(your input goes here)

Output

(the Contrast Ratio Calculator runs in your browser and shows the result instantly)

How to use Contrast Ratio Calculator

1Open the Contrast Ratio Calculator above on MarkVibe — it loads instantly with no sign-up.
2Enter or paste your input into the Contrast Ratio Calculator field.
3Adjust any options to control exactly how Contrast Ratio Calculator produces the result.
4Contrast Ratio Calculator runs locally in your browser and shows the result immediately.
5Copy the output to your clipboard or save it, then share the Contrast Ratio Calculator link with anyone.

Why use our Contrast Ratio Calculator

✓ 100% free Contrast Ratio Calculator — no sign-up, no watermark, no hidden limits
✓ Runs entirely in your browser so your data never leaves your device
✓ Blazing-fast results — built for speed by Markvibe
✓ Mobile-friendly: use Contrast Ratio Calculator on phone, tablet, or desktop
✓ One of 184+ color tools utilities under one roof
✓ Privacy-first: no tracking of inputs, no accounts, no ads in the tool area