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Contrast Ratio vs APCA Contrast Calculator: catalog facts
Contrast Ratio	APCA Contrast Calculator
Free Free to use in the browser.	Free Free to use in the browser.
Web	Web
Updates the ratio live as you type Handles semi-transparent colors with an error margin	Polarity aware, handling dark mode separately Shows contrast relative to font size and weight
Checks one color pair at a time The hosting page includes marketing content from Siege Media	APCA is not yet a published WCAG requirement Results are not the same as WCAG 2 contrast ratios
Web application	Web application
Closed source	Closed source
License not stated	License not stated
No account needed	No account needed
Not stated if it works offline	Needs internet
Official website Full listing and sources Checked September 23, 2026	Official website Full listing and sources Checked October 1, 2026

Catalog facts only. Anything “not stated” is unconfirmed. Check full listings for details.