Short answer
A 7:1 contrast ratio is the WCAG AAA target for normal-size text. It is stricter than the 4.5:1 AA baseline.
When this applies
AAA can be valuable for reading-heavy experiences or critical information, but an interface can still meet WCAG AA without every normal-text pair reaching 7:1.
Practical review steps
- Start by making essential text meet AA.
- Use 7:1 where the design system can support it without changing meaning or hierarchy.
- Do not use a higher ratio as a substitute for clear labels, size, and spacing.
Check the actual color pair
Use the free Contrast Check with the foreground and background colors from the real component. It provides an immediate AA and AAA ratio check in the current browser tab.
Source and limit
For the formal requirement, review W3C's WCAG contrast minimum guidance. A ratio result checks a color pair; it is not a complete accessibility audit.