#637EA0
Closest named color: Off Blue (#5684AE). oklch(58.5% 0.061 254.5), rgb(99, 126, 160).
Aa
Black text reads best on this color (5.02:1).
About this color
#637EA0 is a medium-dark, muted blue. In OKLCH its lightness is 59%, its chroma 0.061 and its hue 254°. Its hue sits on the cool side of the wheel. The nearest named color is Off Blue (#5684AE), ΔE 0.026 away. Black text reads best on it, at 5.02:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | muted (0.061) |
| Temperature | cool |
| Nearest name | Off Blue (#5684AE) |
| Black text | 5.02:1 |
| White text | 4.18:1 |
Values
| HEX | #637EA0 |
| RGB | rgb(99, 126, 160) |
| HSL | hsl(213, 24%, 51%) |
| OKLCH | oklch(58.5% 0.061 254.5) |
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 #637EA0 | 4.18:1 | AA large text | Lc -74.3 | Content text, not long reading |
| Black text on #637EA0 | 5.02:1 | AA | Lc 35.3 | Non-text elements, placeholder text |
| #637EA0 text on white | 4.18:1 | AA large text | Lc 68.8 | Content text, not long reading |
| #637EA0 text on black | 5.02:1 | AA | Lc -32.9 | 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
#728CAB
oklch(63.1% 0.056 253.1)
-
Step 600
600 (this color)
#637EA0
oklch(58.5% 0.061 254.5)
-
Step 700
700
#4A6281
oklch(49% 0.058 255.1)
-
Step 800
800
#3D5069
oklch(42.6% 0.048 255.5)
-
Step 900
900
#344355
oklch(37.7% 0.037 253.3)
-
Step 950
950
#1F2732
oklch(27% 0.024 256.4)
#637EA0 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) | #717FA2 | 0.019 |
| Deuteranopia (no green cones) | #6A799F | 0.016 |
| Tritanopia (no blue cones) | #4F8589 | 0.053 |
| Achromatopsia (no color) | #7C7C7C | 0.061 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637EA0
#637EA0
oklch(58.5% 0.061 254.5)
- #927753
#927753
oklch(58.6% 0.061 74.2)
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 #637EA0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Off Blue #5684AE ΔE 0.026
- Stormy Blue #507B9C ΔE 0.026
- Dusty Blue #5A86AD ΔE 0.026
- Grey Blue #647D8E ΔE 0.028
- Slate Gray #708090 ΔE 0.031
- Cerulean #457B9D ΔE 0.036
- Steel #738595 ΔE 0.037
- Lavender Gray #7E7F9A ΔE 0.038
Use #637EA0 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.