#21978F
Closest named color: Blue Green (#0F9B8E). oklch(61.3% 0.099 187.9), rgb(33, 151, 143).
Aa
Black text reads best on this color (5.88:1).
About this color
#21978F is a medium-dark, moderately saturated teal or cyan. In OKLCH its lightness is 61%, its chroma 0.099 and its hue 188°. Its hue sits on the cool side of the wheel. The nearest named color is Blue Green (#0F9B8E), ΔE 0.013 away. Black text reads best on it, at 5.88:1.
| Hue family | Teals and cyans |
| Lightness | medium-dark (61%) |
| Chroma | moderately saturated (0.099) |
| Temperature | cool |
| Nearest name | Blue Green (#0F9B8E) |
| Black text | 5.88:1 |
| White text | 3.56:1 |
Values
| HEX | #21978F |
| RGB | rgb(33, 151, 143) |
| HSL | hsl(176, 64%, 36%) |
| OKLCH | oklch(61.3% 0.099 187.9) |
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 #21978F | 3.56:1 | AA large text | Lc -68.3 | Content text, not long reading |
| Black text on #21978F | 5.88:1 | AA | Lc 41.2 | Non-text elements, placeholder text |
| #21978F text on white | 3.56:1 | AA large text | Lc 62.8 | Content text, not long reading |
| #21978F text on black | 5.88:1 | AA | Lc -38.8 | Non-text elements, placeholder text |
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 500.
-
Step 50
50
#F1F7F6
oklch(97.1% 0.006 185.3)
-
Step 100
100
#E0EDEB
oklch(93.6% 0.014 185.9)
-
Step 200
200
#C6DFDC
oklch(88.4% 0.027 187.9)
-
Step 300
300
#9ECBC6
oklch(80.9% 0.048 187.9)
-
Step 400
400
#63B0A9
oklch(70.6% 0.077 188)
-
Step 500
500 (this color)
#21978F
oklch(61.3% 0.099 187.9)
-
Step 600
600
#00857E
oklch(55.6% 0.097 188.3)
-
Step 700
700
#00706A
oklch(49.1% 0.085 188.3)
-
Step 800
800
#005C56
oklch(42.8% 0.075 187.1)
-
Step 900
900
#024C48
oklch(37.6% 0.064 188.7)
-
Step 950
950
#082D2A
oklch(27.1% 0.041 187.3)
#21978F 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) | #8E8E8F | 0.105 |
| Deuteranopia (no green cones) | #7E8390 | 0.098 |
| Tritanopia (no blue cones) | #009B94 | 0.012 |
| Achromatopsia (no color) | #888888 | 0.100 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #21978F
#21978F
oklch(61.3% 0.099 187.9)
- #B76A79
#B76A79
oklch(61.4% 0.099 7.9)
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 #21978F, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Blue Green #0F9B8E ΔE 0.013
- Sea #3C9992 ΔE 0.017
- Persian Green #2A9D8F ΔE 0.019
- Teal Green #0A9396 ΔE 0.020
- Dusty Teal #4C9085 ΔE 0.030
- Dark Cyan #008B8B ΔE 0.038
- Ocean Green #3D9973 ΔE 0.045
- Grey Teal #5E9B8A ΔE 0.047
Use #21978F 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.