#637FA1
Closest named color: Dusty Blue (#5A86AD). oklch(58.8% 0.062 253.6), rgb(99, 127, 161).
Aa
Black text reads best on this color (5.08:1).
About this color
#637FA1 is a medium-dark, muted blue. In OKLCH its lightness is 59%, its chroma 0.062 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Dusty Blue (#5A86AD), ΔE 0.024 away. Black text reads best on it, at 5.08:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | muted (0.062) |
| Temperature | cool |
| Nearest name | Dusty Blue (#5A86AD) |
| Black text | 5.08:1 |
| White text | 4.13:1 |
Values
| HEX | #637FA1 |
| RGB | rgb(99, 127, 161) |
| HSL | hsl(213, 25%, 51%) |
| OKLCH | oklch(58.8% 0.062 253.6) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #637FA1 | 4.13:1 | AA large text | Lc -73.9 | Content text, not long reading |
| Black text on #637FA1 | 5.08:1 | AA | Lc 35.7 | Non-text elements, placeholder text |
| #637FA1 text on white | 4.13:1 | AA large text | Lc 68.4 | Content text, not long reading |
| #637FA1 text on black | 5.08:1 | AA | Lc -33.3 | Non-text elements, placeholder text |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 600.
-
Step 50
50
#F4F6F8
oklch(97.2% 0.003 247.9)
-
Step 100
100
#E6EAEF
oklch(93.5% 0.008 253.9)
-
Step 200
200
#D2DAE3
oklch(88.5% 0.015 251.2)
-
Step 300
300
#B5C2D3
oklch(80.9% 0.028 255.1)
-
Step 400
400
#8EA3BC
oklch(70.8% 0.044 252.9)
-
Step 500
500
#728CAC
oklch(63.2% 0.057 253.9)
-
Step 600
600 (this color)
#637FA1
oklch(58.8% 0.062 253.6)
-
Step 700
700
#4A6381
oklch(49.2% 0.057 253.4)
-
Step 800
800
#3D5169
oklch(42.8% 0.047 253.4)
-
Step 900
900
#344355
oklch(37.7% 0.037 253.3)
-
Step 950
950
#1E2732
oklch(26.9% 0.024 253.7)
#637FA1 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #7280A3 | 0.021 |
| Deuteranopia (no green cones) | #6B7AA0 | 0.016 |
| Tritanopia (no blue cones) | #4E878A | 0.055 |
| Achromatopsia (no color) | #7D7D7D | 0.062 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637FA1
#637FA1
oklch(58.8% 0.062 253.6)
- #937753
#937753
oklch(58.7% 0.062 73.1)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #637FA1, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Dusty Blue #5A86AD ΔE 0.024
- Off Blue #5684AE ΔE 0.024
- Stormy Blue #507B9C ΔE 0.028
- Grey Blue #647D8E ΔE 0.029
- Slate Gray #708090 ΔE 0.031
- Steel #738595 ΔE 0.036
- Lavender Gray #7E7F9A ΔE 0.037
- Cerulean #457B9D ΔE 0.038
Use #637FA1 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.