#3F57BB
Closest named color: Iris (#6258C4). oklch(49.5% 0.16 269.6), rgb(63, 87, 187).
Aa
White text reads best on this color (6.37:1).
About this color
#3F57BB is a medium-dark, vivid blue. In OKLCH its lightness is 49%, its chroma 0.160 and its hue 270°. Its hue sits on the cool side of the wheel. The nearest named color is Iris (#6258C4), ΔE 0.051 away. White text reads best on it, at 6.37:1.
| Hue family | Blues |
| Lightness | medium-dark (49%) |
| Chroma | vivid (0.160) |
| Temperature | cool |
| Nearest name | Iris (#6258C4) |
| Black text | 3.29:1 |
| White text | 6.37:1 |
Values
| HEX | #3F57BB |
| RGB | rgb(63, 87, 187) |
| HSL | hsl(228, 50%, 49%) |
| OKLCH | oklch(49.5% 0.16 269.6) |
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 #3F57BB | 6.37:1 | AA | Lc -86.5 | Fine for body text |
| Black text on #3F57BB | 3.29:1 | AA large text | Lc 22.7 | Dividers and decoration only |
| #3F57BB text on white | 6.37:1 | AA | Lc 81.3 | Fine for body text |
| #3F57BB text on black | 3.29:1 | AA large text | Lc -20.5 | Dividers and decoration only |
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 700.
-
Step 50
50
#F3F5FD
oklch(97.1% 0.011 274.9)
-
Step 100
100
#E4EAF9
oklch(93.7% 0.021 268.4)
-
Step 200
200
#CED9F6
oklch(88.6% 0.042 269)
-
Step 300
300
#ADBFF3
oklch(80.9% 0.076 269.8)
-
Step 400
400
#829CEE
oklch(70.7% 0.124 269.7)
-
Step 500
500
#6481E8
oklch(63.1% 0.158 269.6)
-
Step 600
600
#4D68D6
oklch(55.6% 0.171 269.7)
-
Step 700
700 (this color)
#3F57BB
oklch(49.5% 0.16 269.6)
-
Step 800
800
#334796
oklch(42.7% 0.132 269.4)
-
Step 900
900
#2C3C78
oklch(37.6% 0.104 269.6)
-
Step 950
950
#1A2446
oklch(27.1% 0.065 269.4)
#3F57BB 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) | #1265BF | 0.044 |
| Deuteranopia (no green cones) | #005AB9 | 0.040 |
| Tritanopia (no blue cones) | #006F80 | 0.133 |
| Achromatopsia (no color) | #5F5F5F | 0.160 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F57BB
#3F57BB
oklch(49.5% 0.16 269.6)
- #785E00
#785E00
oklch(49.4% 0.101 89.8)
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 #3F57BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Iris #6258C4 ΔE 0.051
- Warm Blue #4B57DB ΔE 0.052
- Mid Blue #276AB3 ΔE 0.055
- French Blue #436BAD ΔE 0.062
- Blue With A Hint Of Purple #533CC6 ΔE 0.065
- Blue Blue #2242C7 ΔE 0.065
- Slate Blue #6A5ACD ΔE 0.068
- Dark Periwinkle #665FD1 ΔE 0.068
Use #3F57BB 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.