#2B21D5
Closest named color: Ultramarine Blue (#1805DB). oklch(42.7% 0.252 270.7), rgb(43, 33, 213).
Aa
White text reads best on this color (9.20:1).
About this color
#2B21D5 is a dark, vivid blue. In OKLCH its lightness is 43%, its chroma 0.252 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Ultramarine Blue (#1805DB), ΔE 0.033 away. White text reads best on it, at 9.20:1.
| Hue family | Blues |
| Lightness | dark (43%) |
| Chroma | vivid (0.252) |
| Temperature | cool |
| Nearest name | Ultramarine Blue (#1805DB) |
| Black text | 2.28:1 |
| White text | 9.20:1 |
Values
| HEX | #2B21D5 |
| RGB | rgb(43, 33, 213) |
| HSL | hsl(243, 73%, 48%) |
| OKLCH | oklch(42.7% 0.252 270.7) |
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 #2B21D5 | 9.20:1 | AAA | Lc -94.0 | Preferred for body text |
| Black text on #2B21D5 | 2.28:1 | Fails | Lc 14.5 | Not readable |
| #2B21D5 text on white | 9.20:1 | AAA | Lc 89.5 | Fine for body text |
| #2B21D5 text on black | 2.28:1 | Fails | Lc -12.8 | 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 800.
-
Step 50
50
#F2F5FF
oklch(97.1% 0.014 272.7)
-
Step 100
100
#E2E9FF
oklch(93.5% 0.031 271.7)
-
Step 200
200
#CBD8FF
oklch(88.5% 0.056 270.7)
-
Step 300
300
#A9BEFF
oklch(80.9% 0.095 270.4)
-
Step 400
400
#7D99FF
oklch(70.7% 0.152 270.5)
-
Step 500
500
#5F7BFF
oklch(63.1% 0.198 270.7)
-
Step 600
600
#4558FF
oklch(55.6% 0.245 270.7)
-
Step 700
700
#362BFF
oklch(49.1% 0.288 270.7)
-
Step 800
800 (this color)
#2B21D5
oklch(42.7% 0.252 270.7)
-
Step 900
900
#2327A7
oklch(37.7% 0.197 270.7)
-
Step 950
950
#131A62
oklch(27% 0.125 270.6)
#2B21D5 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) | #0050DA | 0.078 |
| Deuteranopia (no green cones) | #003ED2 | 0.044 |
| Tritanopia (no blue cones) | #005D7F | 0.190 |
| Achromatopsia (no color) | #484848 | 0.253 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #2B21D5
#2B21D5
oklch(42.7% 0.252 270.7)
- #614C00
#614C00
oklch(42.6% 0.087 90.4)
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 #2B21D5, closest first.
No curated palette has a color within ΔE 0.04 of #2B21D5.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Ultramarine Blue #1805DB ΔE 0.033
- Pure Blue #0203E2 ΔE 0.047
- True Blue #010FCC ΔE 0.048
- Majorelle Blue #3F37C9 ΔE 0.049
- Blue Blue #2242C7 ΔE 0.053
- Medium Blue #0000CD ΔE 0.055
- Strong Blue #0C06F7 ΔE 0.061
- Rich Blue #021BF9 ΔE 0.063
Use #2B21D5 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.