#637BA2
Closest named color: Stormy Blue (#507B9C). oklch(57.9% 0.067 260), rgb(99, 123, 162).
Aa
Black text reads best on this color (4.88:1).
About this color
#637BA2 is a medium-dark, muted blue. In OKLCH its lightness is 58%, its chroma 0.067 and its hue 260°. Its hue sits on the cool side of the wheel. The nearest named color is Stormy Blue (#507B9C), ΔE 0.025 away. Black text reads best on it, at 4.88:1.
| Hue family | Blues |
| Lightness | medium-dark (58%) |
| Chroma | muted (0.067) |
| Temperature | cool |
| Nearest name | Stormy Blue (#507B9C) |
| Black text | 4.88:1 |
| White text | 4.29:1 |
Values
| HEX | #637BA2 |
| RGB | rgb(99, 123, 162) |
| HSL | hsl(217, 25%, 51%) |
| OKLCH | oklch(57.9% 0.067 260) |
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 #637BA2 | 4.29:1 | AA large text | Lc -75.2 | Fine for body text |
| Black text on #637BA2 | 4.88:1 | AA | Lc 34.4 | Non-text elements, placeholder text |
| #637BA2 text on white | 4.29:1 | AA large text | Lc 69.7 | Content text, not long reading |
| #637BA2 text on black | 4.88:1 | AA | Lc -32.0 | 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
#F4F5F8
oklch(97% 0.004 271.4)
-
Step 100
100
#E6EAF0
oklch(93.6% 0.009 258.3)
-
Step 200
200
#D3DAE4
oklch(88.6% 0.016 257.2)
-
Step 300
300
#B6C1D5
oklch(80.9% 0.031 262.5)
-
Step 400
400
#8FA2BF
oklch(70.7% 0.048 258.7)
-
Step 500
500
#748AAF
oklch(63% 0.062 260.7)
-
Step 600
600 (this color)
#637BA2
oklch(57.9% 0.067 260)
-
Step 700
700
#4C6184
oklch(49% 0.062 260.4)
-
Step 800
800
#3E506B
oklch(42.8% 0.051 258.3)
-
Step 900
900
#354257
oklch(37.7% 0.04 259.9)
-
Step 950
950
#1F2733
oklch(27.1% 0.025 258.3)
#637BA2 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) | #6D7DA4 | 0.015 |
| Deuteranopia (no green cones) | #6677A1 | 0.011 |
| Tritanopia (no blue cones) | #4E8388 | 0.059 |
| Achromatopsia (no color) | #7A7A7A | 0.067 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #637BA2
#637BA2
oklch(57.9% 0.067 260)
- #8F764C
#8F764C
oklch(58% 0.066 79.8)
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 #637BA2, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Stormy Blue #507B9C ΔE 0.025
- Off Blue #5684AE ΔE 0.029
- Dusty Blue #5A86AD ΔE 0.032
- Grey Blue #647D8E ΔE 0.034
- Cerulean #457B9D ΔE 0.036
- Dull Blue #49759C ΔE 0.038
- Slate Gray #708090 ΔE 0.039
- Steel Blue #4682B4 ΔE 0.039
Use #637BA2 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.