Contrast Check: #FFFFFF on #000000

White (#FFFFFF) on Black (#000000) — 21.00:1, passes AAA normal.

At a glance

Contrast ratio
21.00:1
WCAG AA (normal text)
Pass
WCAG AA (large text)
Pass
WCAG AAA (normal text)
Pass
UI components / non-text
Pass

White text on a black background is one of the most frequently checked combinations in web design. The measured WCAG 2.1 contrast ratio is 21.00:1. It passes WCAG AAA for body text — the strictest standard. Identical contrast ratio to black-on-white but with a different perceptual feel — APCA scores it slightly differently because it accounts for the polarity asymmetry.

Frequently asked questions

Is #FFFFFF on #000000 accessible?
For WCAG 2.1 AA — the most common conformance target — the answer is yes for normal-size body text. Normal text needs 4.5:1 and this combination measures 21.00:1. Large text (18pt+ or 14pt+ bold) needs only 3:1, so this combination passes for headings and large UI labels. AAA conformance demands 7:1; this combination passes that bar.
Where is this combination commonly used?
Dark-mode body text, terminal interfaces, theatre and concert displays, OLED-friendly UI.
How is this ratio calculated?
WCAG 2.1 contrast ratio is (L1 + 0.05) / (L2 + 0.05) where L1 and L2 are the relative luminances of the lighter and darker colors. Each channel is gamma-corrected (linearized) before applying coefficients 0.2126·R + 0.7152·G + 0.0722·B. The two formulas weight green most because the human eye is most sensitive to green wavelengths.
What if I need a higher ratio than 21.00:1?
This pair already passes AAA — the strictest WCAG 2.1 tier — for body text. You can safely use it anywhere.

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