#21739E
Closest named color: Ocean Blue (#03719C). oklch(52.8% 0.101 236.8), rgb(33, 115, 158).
Aa
White text reads best on this color (5.23:1).
About this color
#21739E is a medium-dark, moderately saturated blue. In OKLCH its lightness is 53%, its chroma 0.101 and its hue 237°. Its hue sits on the cool side of the wheel. The nearest named color is Ocean Blue (#03719C), ΔE 0.013 away. White text reads best on it, at 5.23:1.
| Hue family | Blues |
| Lightness | medium-dark (53%) |
| Chroma | moderately saturated (0.101) |
| Temperature | cool |
| Nearest name | Ocean Blue (#03719C) |
| Black text | 4.01:1 |
| White text | 5.23:1 |
Values
| HEX | #21739E |
| RGB | rgb(33, 115, 158) |
| HSL | hsl(201, 65%, 37%) |
| OKLCH | oklch(52.8% 0.101 236.8) |
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 #21739E | 5.23:1 | AA | Lc -81.0 | Fine for body text |
| Black text on #21739E | 4.01:1 | AA large text | Lc 28.4 | Dividers and decoration only |
| #21739E text on white | 5.23:1 | AA | Lc 75.6 | Fine for body text |
| #21739E text on black | 4.01:1 | AA large text | Lc -26.1 | Dividers and decoration only |
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
#F2F6F9
oklch(97.1% 0.006 239.8)
-
Step 100
100
#E2EBF2
oklch(93.5% 0.014 241)
-
Step 200
200
#CADCE8
oklch(88.5% 0.025 236.9)
-
Step 300
300
#A6C6DB
oklch(81% 0.045 236.9)
-
Step 400
400
#74A8C9
oklch(70.7% 0.073 237)
-
Step 500
500
#4D92BB
oklch(63.2% 0.093 236.9)
-
Step 600
600 (this color)
#21739E
oklch(52.8% 0.101 236.8)
-
Step 700
700
#1D688F
oklch(49.1% 0.094 236.6)
-
Step 800
800
#1B5574
oklch(42.7% 0.078 236.4)
-
Step 900
900
#1D465E
oklch(37.6% 0.061 237.2)
-
Step 950
950
#122937
oklch(26.9% 0.039 237.4)
#21739E 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) | #5E73A0 | 0.058 |
| Deuteranopia (no green cones) | #4D679D | 0.047 |
| Tritanopia (no blue cones) | #007E82 | 0.065 |
| Achromatopsia (no color) | #6C6C6C | 0.102 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21739E
#21739E
oklch(52.8% 0.101 236.8)
- #975A2A
#975A2A
oklch(52.8% 0.102 56.2)
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 #21739E, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Ocean Blue #03719C ΔE 0.013
- Muted Blue #3B719F ΔE 0.019
- Sea Blue #047495 ΔE 0.019
- Flat Blue #3C73A8 ΔE 0.027
- Nice Blue #107AB0 ΔE 0.031
- Dull Blue #49759C ΔE 0.034
- Ocean #017B92 ΔE 0.036
- Cerulean #457B9D ΔE 0.040
Use #21739E 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.