Color blind friendly spinner wheel

A wheel spinner designed for red-green color blindness

Around 8% of men of European ancestry have some form of red-green color deficiency, as do between 4% and 6.5% of men of Chinese and Japanese ancestry. On standard spinner wheels that use saturated rainbow primaries, adjacent red and green slices blur together for attendees with deuteranopia or protanopia, making it difficult to follow the wheel from across a classroom or meeting room.

This wheel solves that visual ambiguity in two ways: first, by rendering slices in a palette engineered specifically for color vision deficiency; second, by enforcing that color is never the only channel carrying information. Every slice carries high-contrast text, outcomes are announced in words, and the wheel remains fully usable even in greyscale.

Source: Jennifer Birch, “Worldwide prevalence of red-green color deficiency”, Journal of the Optical Society of America A 29(3), 2012, 313–320.

Which colors does this wheel use?

Six of the eight colors from the palette published by Masataka Okabe and Kei Ito in their guide to color universal design, used exactly as they set them down: orange, sky blue, bluish green, blue, vermillion and reddish purple. Their pale yellow is left out for a reason that has nothing to do with color vision: on a light background it is barely darker than the page, so a slice of it has no visible edge.

The spacing of the remaining six is the whole point of them, and it does not survive being adjusted to taste. Measured after simulating red-green deficiency, Okabe and Ito's set maintains a comfortable margin of about fourteen to nineteen units of perceptual difference (ΔE) between its closest pairs, compared to less than three in arbitrary rainbow palettes.

Source: Masataka Okabe and Kei Ito, “Color Universal Design (CUD): how to make figures and presentations that are friendly to colorblind people”, 2008.

What this page does not claim

It is honest about red against green, which is what nearly everyone with a color vision deficiency has. It does not eliminate perceptual overlap for tritanopia, which affects the blue-yellow axis and is far rarer, nor can any color palette help someone who sees no color at all.

So the rule that actually protects the wheel is that color is never the only channel: every slice carries its label in high-contrast ink, crowded lists switch to numbers and a named legend, winners are announced in words to screen readers, and the wheel remains fully usable in black and white.

How does this wheel ensure fair odds?

Every spin is decided before the animation begins using the browser's cryptographic random number generator (crypto.getRandomValues) converted to a 53-bit float. Slice angle always equals mathematical probability, and there are no hidden weights or physics simulations that can be manipulated.

The editor takes any list — paste up to 1,000 names directly from a spreadsheet, or weight rows individually. Click Remove on a winner to draw without replacement so nobody wins twice, enter ad-free fullscreen present mode for a room, and share your wheel as a URL query string with no login or account required.