#173299
Closest named color: Sapphire (#2138AB). oklch(37.4% 0.17 266.2), rgb(23, 50, 153).
Aa
White text reads best on this color (10.75:1).
About this color
#173299 is a dark, vivid blue. In OKLCH its lightness is 37%, its chroma 0.170 and its hue 266°. Its hue sits on the cool side of the wheel. The nearest named color is Sapphire (#2138AB), ΔE 0.036 away. White text reads best on it, at 10.75:1.
| Hue family | Blues |
| Lightness | dark (37%) |
| Chroma | vivid (0.170) |
| Temperature | cool |
| Nearest name | Sapphire (#2138AB) |
| Black text | 1.95:1 |
| White text | 10.75:1 |
Values
| HEX | #173299 |
| RGB | rgb(23, 50, 153) |
| HSL | hsl(228, 74%, 35%) |
| OKLCH | oklch(37.4% 0.17 266.2) |
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 #173299 | 10.75:1 | AAA | Lc -98.1 | Preferred for body text |
| Black text on #173299 | 1.95:1 | Fails | Lc 9.8 | Not readable |
| #173299 text on white | 10.75:1 | AAA | Lc 94.1 | Preferred for body text |
| #173299 text on black | 1.95:1 | Fails | Lc -8.4 | Not readable |
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 900.
-
Step 50
50
#F1F5FF
oklch(97% 0.014 268.5)
-
Step 100
100
#E0EAFF
oklch(93.6% 0.03 265.3)
-
Step 200
200
#C8D9FF
oklch(88.5% 0.056 266.2)
-
Step 300
300
#A4C0FF
oklch(81% 0.095 265.8)
-
Step 400
400
#749CFF
oklch(70.8% 0.152 266)
-
Step 500
500
#517FFF
oklch(63.2% 0.197 266)
-
Step 600
600
#315DFF
oklch(55.6% 0.244 266.2)
-
Step 700
700
#1E3FF2
oklch(49% 0.263 266.1)
-
Step 800
800
#1937C4
oklch(42.8% 0.218 266.1)
-
Step 900
900 (this color)
#173299
oklch(37.4% 0.17 266.2)
-
Step 950
950
#0E1F5A
oklch(26.9% 0.108 266.5)
#173299 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) | #00449C | 0.043 |
| Deuteranopia (no green cones) | #003897 | 0.017 |
| Tritanopia (no blue cones) | #004E61 | 0.131 |
| Achromatopsia (no color) | #3E3E3E | 0.171 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #173299
#173299
oklch(37.4% 0.17 266.2)
- #533D00
#533D00
oklch(37.4% 0.077 85.6)
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 #173299, closest first.
No curated palette has a color within ΔE 0.04 of #173299.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Sapphire #2138AB ΔE 0.036
- Royal #0C1793 ΔE 0.056
- Cobalt #1E488F ΔE 0.061
- Indigo Blue #3A18B1 ΔE 0.064
- Ultramarine #2000B1 ΔE 0.066
- Cobalt Blue #030AA7 ΔE 0.066
- Twilight Blue #0A437A ΔE 0.070
- Blueberry #464196 ΔE 0.076
Use #173299 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.