OKLCH and Accessibility
OKLCH makes contrast easier to reason about — but it does not replace real WCAG contrast checks. Here's how to combine them.
Updated Jul 1, 2026 · By OKLCH.xyz editorial team
Because OKLCH lightness is perceptual, it is a great starting point for accessible color — but it is not a contrast metric by itself.
Don’t fake contrast from lightness
A tempting shortcut is abs(L1 − L2). Do not use it for WCAG decisions. WCAG 2.x
contrast is a ratio of relative luminance, computed from linearized sRGB, not from
OKLCH lightness. The contrast checker uses the correct formula.
The thresholds
- 4.5:1 — normal text, AA
- 3:1 — large text and UI components
- 7:1 — normal text, AAA
Nearest accessible color
When a pair fails, you rarely want to throw the color away. The checker holds hue and chroma constant and moves only lightness to reach the nearest passing value — so the fixed color still belongs to your palette.
APCA
APCA is a newer, perceptually-based contrast method. It is promising but still experimental; treat its Lc numbers as a preview alongside WCAG, not a replacement.
Calculation methodology
WCAG ratios are calculated after alpha compositing in sRGB; APCA is displayed separately as an experimental metric.