#3F7DCB
Closest named color: Windows Blue (#3778BF). oklch(58.6% 0.136 255.4), rgb(63, 125, 203).
Aa
Black text reads best on this color (5.00:1).
About this color
#3F7DCB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 59%, its chroma 0.136 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Windows Blue (#3778BF), ΔE 0.023 away. Black text reads best on it, at 5.00:1.
| Hue family | Blues |
| Lightness | medium-dark (59%) |
| Chroma | moderately saturated (0.136) |
| Temperature | cool |
| Nearest name | Windows Blue (#3778BF) |
| Black text | 5.00:1 |
| White text | 4.19:1 |
Values
| HEX | #3F7DCB |
| RGB | rgb(63, 125, 203) |
| HSL | hsl(213, 57%, 52%) |
| OKLCH | oklch(58.6% 0.136 255.4) |
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 #3F7DCB | 4.19:1 | AA large text | Lc -74.1 | Content text, not long reading |
| Black text on #3F7DCB | 5.00:1 | AA | Lc 35.5 | Non-text elements, placeholder text |
| #3F7DCB text on white | 4.19:1 | AA large text | Lc 68.6 | Content text, not long reading |
| #3F7DCB text on black | 5.00:1 | AA | Lc -33.0 | 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
#E2EBF6
oklch(93.7% 0.018 253.3)
-
Step 200
200
#CBDBF0
oklch(88.6% 0.034 255.2)
-
Step 300
300
#A7C3E8
oklch(80.9% 0.061 255.5)
-
Step 400
400
#77A3DD
oklch(70.7% 0.098 255.6)
-
Step 500
500
#538BD4
oklch(63.1% 0.126 255.7)
-
Step 600
600 (this color)
#3F7DCB
oklch(58.6% 0.136 255.4)
-
Step 700
700
#2861A7
oklch(49.2% 0.127 255.3)
-
Step 800
800
#234F87
oklch(42.7% 0.105 255.7)
-
Step 900
900
#21426C
oklch(37.6% 0.082 255.4)
-
Step 950
950
#14273F
oklch(27% 0.052 255)
#3F7DCB 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) | #5A83CE | 0.034 |
| Deuteranopia (no green cones) | #4476C9 | 0.019 |
| Tritanopia (no blue cones) | #008F9A | 0.107 |
| Achromatopsia (no color) | #7C7C7C | 0.136 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F7DCB
#3F7DCB
oklch(58.6% 0.136 255.4)
- #A67000
#A67000
oklch(58.7% 0.124 75.5)
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 #3F7DCB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Windows Blue #3778BF ΔE 0.023
- Water Blue #0E87CC ΔE 0.033
- Cool Blue #4984B8 ΔE 0.040
- Steel Blue #4682B4 ΔE 0.042
- Nice Blue #107AB0 ΔE 0.053
- Dark Sky Blue #448EE4 ΔE 0.056
- Flat Blue #3C73A8 ΔE 0.057
- Off Blue #5684AE ΔE 0.058
Use #3F7DCB 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.