#042BB1
Closest named color: Sapphire (#2138AB). oklch(38.4% 0.211 264.2), rgb(4, 43, 177).
Aa
White text reads best on this color (10.57:1).
About this color
#042BB1 is a dark, vivid blue. In OKLCH its lightness is 38%, its chroma 0.211 and its hue 264°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.037 away. White text reads best on it, at 10.57:1.
| Hue family | Blues |
| Lightness | dark (38%) |
| Chroma | vivid (0.211) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 1.98:1 |
| White text | 10.57:1 |
Values
| HEX | #042BB1 |
| RGB | rgb(4, 43, 177) |
| HSL | hsl(226, 96%, 35%) |
| OKLCH | oklch(38.4% 0.211 264.2) |
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 #042BB1 | 10.57:1 | AAA | Lc -97.2 | Preferred for body text |
| Black text on #042BB1 | 1.98:1 | Fails | Lc 10.8 | Not readable |
| #042BB1 text on white | 10.57:1 | AAA | Lc 93.1 | Preferred for body text |
| #042BB1 text on black | 1.98:1 | Fails | Lc -9.4 | 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
#F1F6FF
oklch(97.2% 0.013 262.4)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C7DAFF
oklch(88.6% 0.055 263.7)
-
Step 300
300
#A2C0FF
oklch(80.9% 0.096 264.7)
-
Step 400
400
#709DFF
oklch(70.7% 0.152 264.2)
-
Step 500
500
#4A80FF
oklch(63.1% 0.198 264.2)
-
Step 600
600
#245FFF
oklch(55.6% 0.245 264.2)
-
Step 700
700
#0338FF
oklch(49.1% 0.287 264.2)
-
Step 800
800
#0021DF
oklch(42.7% 0.27 264.2)
-
Step 900
900 (this color)
#042BB1
oklch(38.4% 0.211 264.2)
-
Step 950
950
#041B66
oklch(27% 0.133 264.3)
#042BB1 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) | #0047B5 | 0.061 |
| Deuteranopia (no green cones) | #0036AF | 0.021 |
| Tritanopia (no blue cones) | #00536C | 0.158 |
| Achromatopsia (no color) | #3F3F3F | 0.212 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #042BB1
#042BB1
oklch(38.4% 0.211 264.2)
- #573F00
#573F00
oklch(38.4% 0.079 84.1)
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 #042BB1, closest first.
No curated palette has a color within ΔE 0.04 of #042BB1.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.037
- Ultramarine #2000B1 ΔE 0.043
- True Blue #010FCC ΔE 0.049
- Cobalt Blue #030AA7 ΔE 0.050
- Medium Blue #0000CD ΔE 0.055
- Indigo Blue #3A18B1 ΔE 0.057
- Royal #0C1793 ΔE 0.065
- Blue Blue #2242C7 ΔE 0.069
Use #042BB1 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.