Color Contrast Checker
Pick a wall color and a trim, molding, or frame color and see exactly how much they stand apart, using the WCAG relative-luminance formula.
Contrast ratio
How the ratio is calculated
Each color is converted from its hex code into linear-light red, green, and blue values, combined into a single relative-luminance number (green contributes the most to perceived brightness, blue the least), and then the lighter and darker of the two luminances are plugged into (L1 + 0.05) / (L2 + 0.05). That formula is the WCAG 2.x standard, so the ratio this tool reports matches what any accessibility contrast checker would return for the same two colors.
For interior design, the practical use is simple: a low ratio means two colors will visually blend into each other from across the room, while a high ratio means they'll read as clearly separate elements — useful whether you're pairing a wall color with trim, choosing frame colors for a gallery wall, or picking an accent that won't disappear against its neighbor.
Frequently Asked Questions
What does a contrast ratio actually measure?
It's a number from 1:1 (identical colors) to 21:1 (pure black against pure white) that describes how much two colors' brightness differs, based on their relative luminance — how much light each color effectively reflects. The higher the ratio, the easier it is for the eye to separate one color from the other.
Why use the WCAG accessibility formula for a decorating decision?
The WCAG (Web Content Accessibility Guidelines) contrast formula is a rigorously defined, widely implemented way to quantify "do these two colors stand apart," originally built for screen text but equally useful for a wall: trim against a wall color, artwork mats against a wall, or gallery-wall frames against your paint. It replaces a guess with a number.
What ratio should I aim for?
For trim, molding, or wainscoting you want to clearly read as separate from the wall, aim for at least 3:1 (the WCAG "AA large text" threshold) and ideally 4.5:1 or higher. For a wall meant as a backdrop for artwork, a lower ratio (a closer color match) can be the better design choice — the tool reports the number either way so you can decide.
Does this account for paint sheen or lighting?
No — the ratio is calculated from the two hex colors alone, the same way a screen would render them. Glossy sheens, warm bulbs, and natural light all shift how a color actually looks on your wall, so treat the result as a starting point and confirm with a physical paint sample under your room's real lighting.
Educational tool only. The ratio reflects the two hex colors as entered — actual paint sheen, lighting, and finish will change how a color looks in person.