#3977CB
Closest named color: Windows Blue (#3778BF). oklch(57.1% 0.145 256.8), rgb(57, 119, 203).
Aa
Black text reads best on this color (4.67:1).
About this color
#3977CB is a medium-dark, vivid blue. In OKLCH its lightness is 57%, its chroma 0.145 and its hue 257°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.020 away. Black text reads best on it, at 4.67:1.
| Hue family | Blues |
| Lightness | medium-dark (57%) |
| Chroma | vivid (0.145) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 4.67:1 |
| White text | 4.49:1 |
Values
| HEX | #3977CB |
| RGB | rgb(57, 119, 203) |
| HSL | hsl(215, 58%, 51%) |
| OKLCH | oklch(57.1% 0.145 256.8) |
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 #3977CB | 4.49:1 | AA large text | Lc -76.3 | Fine for body text |
| Black text on #3977CB | 4.67:1 | AA | Lc 33.2 | Non-text elements, placeholder text |
| #3977CB text on white | 4.49:1 | AA large text | Lc 70.8 | Content text, not long reading |
| #3977CB text on black | 4.67:1 | AA | Lc -30.8 | 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 600.
-
Step 50
50
#F2F6FB
oklch(97.2% 0.008 253.9)
-
Step 100
100
#E2EBF7
oklch(93.7% 0.019 255.5)
-
Step 200
200
#CADBF1
oklch(88.6% 0.035 254.9)
-
Step 300
300
#A6C3EB
oklch(80.9% 0.065 256.5)
-
Step 400
400
#76A3E1
oklch(70.8% 0.104 256.6)
-
Step 500
500
#518AD9
oklch(63.1% 0.134 256.9)
-
Step 600
600 (this color)
#3977CB
oklch(57.1% 0.145 256.8)
-
Step 700
700
#2760AB
oklch(49.2% 0.134 256.6)
-
Step 800
800
#224E8B
oklch(42.7% 0.112 257.3)
-
Step 900
900
#21426F
oklch(37.8% 0.087 256.7)
-
Step 950
950
#142741
oklch(27.1% 0.055 256.6)
#3977CB 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) | #4F7ECE | 0.030 |
| Deuteranopia (no green cones) | #3771C9 | 0.017 |
| Tritanopia (no blue cones) | #008B97 | 0.114 |
| Achromatopsia (no color) | #777777 | 0.145 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3977CB
#3977CB
oklch(57.1% 0.145 256.8)
- #9F6C00
#9F6C00
oklch(57% 0.12 76.2)
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 #3977CB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.020
- Water Blue #0E87CC ΔE 0.045
- Nice Blue #107AB0 ΔE 0.051
- French Blue #436BAD ΔE 0.052
- Royal Blue #4169E1 ΔE 0.053
- Mid Blue #276AB3 ΔE 0.053
- Flat Blue #3C73A8 ΔE 0.054
- Steel Blue #4682B4 ΔE 0.054
Use #3977CB 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.