#21B5A0
Closest named color: Greeny Blue (#42B395). oklch(69.6% 0.12 180.1), rgb(33, 181, 160).
Aa
Black text reads best on this color (8.18:1).
About this color
#21B5A0 is a medium-light, moderately saturated teal or cyan. In OKLCH its lightness is 70%, its chroma 0.120 and its hue 180°. Its hue sits on the cool side of the wheel. The nearest named color is Greeny Blue (#42B395), ΔE 0.018 away. Black text reads best on it, at 8.18:1.
| Hue family | Teals and cyans |
| Lightness | medium-light (70%) |
| Chroma | moderately saturated (0.120) |
| Temperature | cool |
| Nearest name | Greeny Blue (#42B395) |
| Black text | 8.18:1 |
| White text | 2.56:1 |
Values
| HEX | #21B5A0 |
| RGB | rgb(33, 181, 160) |
| HSL | hsl(171, 69%, 42%) |
| OKLCH | oklch(69.6% 0.12 180.1) |
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 #21B5A0 | 2.56:1 | Fails | Lc -54.8 | Large or bold text, headings |
| Black text on #21B5A0 | 8.18:1 | AAA | Lc 54.3 | Large or bold text, headings |
| #21B5A0 text on white | 2.56:1 | Fails | Lc 49.7 | Large or bold text, headings |
| #21B5A0 text on black | 8.18:1 | AAA | Lc -52.2 | Large or bold text, headings |
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 400.
-
Step 50
50
#EFF8F6
oklch(97.2% 0.01 181.4)
-
Step 100
100
#DBEFEA
oklch(93.6% 0.022 179.2)
-
Step 200
200
#BCE3DA
oklch(88.5% 0.043 179.7)
-
Step 300
300
#89D1C2
oklch(80.9% 0.075 179.7)
-
Step 400
400 (this color)
#21B5A0
oklch(69.6% 0.12 180.1)
-
Step 500
500
#00A08C
oklch(63.2% 0.115 179.7)
-
Step 600
600
#008676
oklch(55.6% 0.1 180.5)
-
Step 700
700
#007163
oklch(49.2% 0.089 180.3)
-
Step 800
800
#005C51
oklch(42.6% 0.077 181.1)
-
Step 900
900
#004D43
oklch(37.7% 0.068 180.3)
-
Step 950
950
#002E27
oklch(27% 0.049 179.5)
#21B5A0 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) | #ADAA9F | 0.127 |
| Deuteranopia (no green cones) | #9A9CA2 | 0.121 |
| Tritanopia (no blue cones) | #00B8AF | 0.021 |
| Achromatopsia (no color) | #A2A2A2 | 0.121 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21B5A0
#21B5A0
oklch(69.6% 0.12 180.1)
- #D97C9A
#D97C9A
oklch(69.6% 0.12 0)
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 #21B5A0, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Greeny Blue #42B395 ΔE 0.018
- Light Sea Green #20B2AA ΔE 0.020
- Topaz #13BBAF ΔE 0.023
- Green Blue #01C08D ΔE 0.049
- Bluey Green #2BB179 ΔE 0.053
- Dark Seafoam #1FB57A ΔE 0.055
- Dark Seafoam Green #3EAF76 ΔE 0.055
- Tea #65AB7C ΔE 0.056
Use #21B5A0 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.