KuConvert

Colour

Pick a colour and see everything about it

Pick or paste a colour to get it in every notation, with a lightness scale, the harmonies a colour wheel describes, and whether text on it will actually be readable.

#ff8800

HEX

255, 136, 0

RGB

32, 100%, 50%

HSL

Every notation

Preview

White text on thisBlack text on this

Contrast

  • Against white2.39:1Fails
  • Against black8.77:1AAA

WCAG asks for 4.5:1 for body text and 3:1 for large text. The ratio is computed from relative luminance, which is not the same as how bright a colour looks.

Shades

Lightness steps, keeping the hue and saturation. Click any swatch to copy it.

Harmonies

Complementary

Analogous

Triadic

Split complementary

  • Runs in your browser
  • No account required
  • Free to use

How it works

01

Contrast is computed the way WCAG defines it

Relative luminance is not brightness. The channel transfer function is linear below a small threshold and a power curve above it, and using a plain 2.2 gamma instead gives ratios that are close but wrong — which matters when the number decides whether a design passes an accessibility check.

02

Shades change lightness, not the mix

The scale moves along HSL lightness rather than mixing toward white and black. Mixing shifts the hue and washes out the saturation, so the pale end stops looking like the colour you started with.

03

Harmonies are hue rotations

Complementary is 180° away, triadic is 120° apart, analogous is 30° either side. Saturation and lightness are held, so the set reads as one family rather than a row of unrelated colours.

What it does

Every notation at once

HEX, RGB and HSL, with alpha where you gave one. Paste any of the three and get the other two.

Contrast against white and black

With the AA and AAA verdicts, because “readable” depends entirely on what the colour sits on.

Shades and harmonies

A nine-step lightness scale and four harmony sets, each swatch click-to-copy.

Runs in your browser

No account and no upload — what you type is never sent anywhere. Analytics records that the tool was opened, never what you put into it.

Practical advice

Getting a better result

  • Aim for 4.5:1 for body text and 3:1 for large text. Below 3:1 the text is hard work for everyone, not only people with low vision.
  • A colour that fails against white often passes against black. Checking both is faster than guessing.
  • HSL is the notation to reach for when building a scale — changing one number gives you a lighter version of the same colour.

Questions

Things people ask

What contrast ratio do I need?

WCAG AA asks for 4.5:1 for normal text and 3:1 for large text — 18pt, or 14pt bold. AAA raises those to 7:1 and 4.5:1. The ratio runs from 1:1, identical colours, to 21:1, black on white.

Why does my colour look brighter than its contrast suggests?

Because perceived brightness and relative luminance are not the same thing. Yellow looks bright and has high luminance, so dark text on it passes easily; a saturated blue can look vivid while having low luminance. The ratio follows the maths, not the impression.

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Who builds these

Free tools by day. Websites that earn their keep by trade.

KuConvert is built by KUDUY, a web design and development agency. From custom WordPress builds to SEO and e-commerce, everything they do is engineered to bring you more qualified traffic and turn it into revenue.

Web Design

Custom, conversion-focused web design that captivates visitors and turns them into paying customers. Mobile-first, fast, and built to rank.

Web Development

Custom WordPress websites built with clean code, blazing-fast performance (Core Web Vitals optimised), and enterprise-grade security.

E-Commerce

Online stores that convert visitors to customers with seamless shopping experiences.

SEO

Technical SEO, keyword research, on-page optimisation and local SEO strategies that drive qualified organic traffic.

Digital Marketing

Data-driven campaigns that deliver measurable ROI across every channel.

Branding

Memorable brand identities that stand out in any market and build lasting trust.

Website Help

One-on-one expert support for bug fixes, updates and ongoing maintenance — without a long-term retainer.

  • Fixed scope, no surprise invoices

    Most sites ship in four to eight weeks with the scope and the price agreed up front.

  • SEO from day one

    Search is designed into the build — structure, schema and Core Web Vitals — not retrofitted.

  • A team, not a ticket queue

    A project manager, a designer and a developer you can actually reach.

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This tool runs entirely in your browser. Your files are never uploaded.