#3370BB
Closest named color: Mid Blue (#276AB3). oklch(54.3% 0.133 255.1), rgb(51, 112, 187).
Aa
White text reads best on this color (5.02:1).
About this color
#3370BB is a medium-dark, moderately saturated blue. In OKLCH its lightness is 54%, its chroma 0.133 and its hue 255°. Its hue sits on the cool side of the wheel. The nearest named color is Mid Blue (#276AB3), ΔE 0.023 away. White text reads best on it, at 5.02:1.
| Hue family | Blues |
| Lightness | medium-dark (54%) |
| Chroma | moderately saturated (0.133) |
| Temperature | cool |
| Nearest name | Mid Blue (#276AB3) |
| Black text | 4.17:1 |
| White text | 5.02:1 |
Values
| HEX | #3370BB |
| RGB | rgb(51, 112, 187) |
| HSL | hsl(213, 57%, 47%) |
| OKLCH | oklch(54.3% 0.133 255.1) |
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 #3370BB | 5.02:1 | AA | Lc -79.8 | Fine for body text |
| Black text on #3370BB | 4.17:1 | AA large text | Lc 29.6 | Dividers and decoration only |
| #3370BB text on white | 5.02:1 | AA | Lc 74.4 | Content text, not long reading |
| #3370BB text on black | 4.17:1 | AA large text | Lc -27.3 | 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 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
#CBDBEF
oklch(88.6% 0.033 254)
-
Step 300
300
#A7C3E7
oklch(80.9% 0.06 254.8)
-
Step 400
400
#77A3DC
oklch(70.6% 0.097 255.2)
-
Step 500
500
#548BD2
oklch(63% 0.123 255.5)
-
Step 600
600 (this color)
#3370BB
oklch(54.3% 0.133 255.1)
-
Step 700
700
#2961A5
oklch(49.1% 0.124 255.1)
-
Step 800
800
#234F86
oklch(42.6% 0.104 255.4)
-
Step 900
900
#22426B
oklch(37.6% 0.08 255.5)
-
Step 950
950
#15273F
oklch(27% 0.051 256.1)
#3370BB 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) | #4D76BE | 0.032 |
| Deuteranopia (no green cones) | #3769B9 | 0.019 |
| Tritanopia (no blue cones) | #00828C | 0.104 |
| Achromatopsia (no color) | #6F6F6F | 0.133 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #3370BB
#3370BB
oklch(54.3% 0.133 255.1)
- #966400
#966400
oklch(54.3% 0.115 74.8)
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 #3370BB, closest first.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Mid Blue #276AB3 ΔE 0.023
- Windows Blue #3778BF ΔE 0.023
- French Blue #436BAD ΔE 0.026
- Flat Blue #3C73A8 ΔE 0.034
- Nice Blue #107AB0 ΔE 0.039
- Muted Blue #3B719F ΔE 0.045
- Ocean Blue #03719C ΔE 0.057
- Dull Blue #49759C ΔE 0.057
Use #3370BB 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.