It turns colour into a number.
Colour tools turn visual choices into measurable values such as contrast ratios or colour coordinates. That makes them useful checks, not automatic design decisions.
Colour & Accessibility
Build a palette around this colour.
Generate complementary, analogous and triadic-style hue rotations as a quick starting point.
Base colour
Harmony starting points
#F45B1F
#F4C51F
#1FF45B
#1FB8F4
#5B1FF4
#F41F4D
These are simple hue rotations. Treat them as starting points, then adjust saturation/lightness optically.
Useful to know
Four things worth knowing.
Passing is not the whole design.
A passing number cannot judge hierarchy, glare, display calibration, print stock or whether the surrounding design is actually readable.
Check it at real size.
Use the number as a signal, then look at the real text size, weight, background and surrounding colours.
Treat the number as a floor.
Check the real size and context after the number passes. Small text and thin weights usually need more breathing room than the minimum.