#3F51BE
Closest named color: Warm Blue (#4B57DB). oklch(48.5% 0.171 271.4), rgb(63, 81, 190).
Aa
White text reads best on this color (6.70:1).
About this color
#3F51BE is a medium-dark, vivid blue. In OKLCH its lightness is 49%, its chroma 0.171 and its hue 271°. Its hue sits on the cool side of the wheel. The nearest named color is Warm Blue (#4B57DB), ΔE 0.050 away. White text reads best on it, at 6.70:1.
| Hue family | Blues |
| Lightness | medium-dark (49%) |
| Chroma | vivid (0.171) |
| Temperature | cool |
| Nearest name | Warm Blue (#4B57DB) |
| Black text | 3.13:1 |
| White text | 6.70:1 |
Values
| HEX | #3F51BE |
| RGB | rgb(63, 81, 190) |
| HSL | hsl(231, 50%, 50%) |
| OKLCH | oklch(48.5% 0.171 271.4) |
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 #3F51BE | 6.70:1 | AA | Lc -87.7 | Fine for body text |
| Black text on #3F51BE | 3.13:1 | AA large text | Lc 21.4 | Dividers and decoration only |
| #3F51BE text on white | 6.70:1 | AA | Lc 82.7 | Fine for body text |
| #3F51BE text on black | 3.13:1 | AA large text | Lc -19.3 | 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
#E4E9FB
oklch(93.6% 0.025 273.5)
-
Step 200
200
#CED8F9
oklch(88.5% 0.047 272.1)
-
Step 300
300
#ADBEF7
oklch(80.9% 0.083 271.6)
-
Step 400
400
#839AF3
oklch(70.6% 0.133 271.7)
-
Step 500
500
#667FEF
oklch(63.2% 0.169 271.3)
-
Step 600
600
#4F65DD
oklch(55.6% 0.184 271.3)
-
Step 700
700 (this color)
#3F51BE
oklch(48.5% 0.171 271.4)
-
Step 800
800
#35449B
oklch(42.6% 0.142 271.6)
-
Step 900
900
#2D3B7B
oklch(37.7% 0.11 271)
-
Step 950
950
#1A2348
oklch(27% 0.07 270.8)
#3F51BE 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) | #0062C2 | 0.052 |
| Deuteranopia (no green cones) | #0056BC | 0.042 |
| Tritanopia (no blue cones) | #006C7F | 0.142 |
| Achromatopsia (no color) | #5C5C5C | 0.172 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3F51BE
#3F51BE
oklch(48.5% 0.171 271.4)
- #745C00
#745C00
oklch(48.5% 0.099 91)
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 #3F51BE, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Warm Blue #4B57DB ΔE 0.050
- Blue With A Hint Of Purple #533CC6 ΔE 0.051
- Blue Blue #2242C7 ΔE 0.052
- Iris #6258C4 ΔE 0.055
- Majorelle Blue #3F37C9 ΔE 0.057
- Blurple #5539CC ΔE 0.059
- Bluey Purple #6241C7 ΔE 0.060
- Mid Blue #276AB3 ΔE 0.070
Use #3F51BE 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.