#00397B
Closest named color: Marine Blue (#01386A). oklch(35.5% 0.125 256.7), rgb(0, 57, 123).
Aa
White text reads best on this color (11.22:1).
About this color
#00397B is a dark, moderately saturated blue. In OKLCH its lightness is 36%, its chroma 0.125 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Marine Blue (#01386A), ΔE 0.029 away. White text reads best on it, at 11.22:1.
| Hue family | Blues |
| Lightness | dark (36%) |
| Chroma | moderately saturated (0.125) |
| Temperature | cool |
| Nearest name | Marine Blue (#01386A) |
| Black text | 1.87:1 |
| White text | 11.22:1 |
Values
| HEX | #00397B |
| RGB | rgb(0, 57, 123) |
| HSL | hsl(212, 100%, 24%) |
| OKLCH | oklch(35.5% 0.125 256.7) |
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 #00397B | 11.22:1 | AAA | Lc -99.1 | Preferred for body text |
| Black text on #00397B | 1.87:1 | Fails | Lc 8.7 | Not readable |
| #00397B text on white | 11.22:1 | AAA | Lc 95.2 | Preferred for body text |
| #00397B text on black | 1.87:1 | Fails | Lc -7.4 | Not readable |
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 900.
-
Step 50
50
#F0F6FE
oklch(97.1% 0.012 255.5)
-
Step 100
100
#DFEBFC
oklch(93.6% 0.026 257)
-
Step 200
200
#C4DBFC
oklch(88.5% 0.052 257.4)
-
Step 300
300
#9AC3FD
oklch(80.9% 0.094 257.1)
-
Step 400
400
#5FA1FC
oklch(70.6% 0.15 256.8)
-
Step 500
500
#2C87FA
oklch(63.2% 0.191 256.6)
-
Step 600
600
#006EE2
oklch(55.6% 0.196 256.8)
-
Step 700
700
#005CBF
oklch(49% 0.172 256.8)
-
Step 800
800
#004B9E
oklch(42.6% 0.15 256.7)
-
Step 900
900 (this color)
#00397B
oklch(35.5% 0.125 256.7)
-
Step 950
950
#08264C
oklch(27.1% 0.079 256.3)
#00397B 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) | #08407D | 0.022 |
| Deuteranopia (no green cones) | #00367A | 0.009 |
| Tritanopia (no blue cones) | #004954 | 0.093 |
| Achromatopsia (no color) | #3B3B3B | 0.125 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #00397B
#00397B
oklch(35.5% 0.125 256.7)
- #523600
#523600
oklch(35.7% 0.075 76.7)
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 #00397B, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Marine Blue #01386A ΔE 0.029
- Twilight Blue #0A437A ΔE 0.031
- Marine #042E60 ΔE 0.055
- Cobalt #1E488F ΔE 0.059
- Prussian Blue #1D3557 ΔE 0.063
- Light Navy #155084 ΔE 0.071
- Midnight Blue #191970 ΔE 0.079
- Royal #0C1793 ΔE 0.080
Use #00397B 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.