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blue · cool

#103c9a

a dark, electric blue · cool · closest name: Dark Slate Blue

Token name suggestion: Forest Harbour

RGB
16, 60, 154
HSL
221°, 81%, 33%
CMYK
90, 61, 0, 40
Luminance
0.0567

#103c9a is a dark electric blue, 221° on the wheel and 94/100 on the cool side. Put white text on it (9.84:1). As text it scores 9.84:1 on white — safe at any size. Nearest name is Dark Slate Blue, nearest Tailwind family is indigo.

hsl(221 81% 33%)rgb(16 60 154)Base step 800AAA inkCool

At a glance

Every number on this page in one read: what #103c9a is made of, how bright it looks, and which way it leans.

Hex
#103c9a
Hue
221°
blue
Saturation
81%
electric
Lightness
33%
dark
Brightness
60%
HSV value
Perceived
27%
weighted brightness
Luminance
0.0567
WCAG relative
Temperature
Cool
94/100 cool
Color family
Blue
Tone
Electric
Best ink
White
9.84:1
Closest name
Dark Slate Blue
ΔE2000 8
Chroma
60.0
LCH, 0–130ish
OKLCH L
0.393
perceptual lightness
Tailwind
indigo
500 · ΔE 19.4
Web-safe
#003399
nearest of 216
Where it sits
Hue221° of 360°
Saturation81%
Lightness33%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #103c9a.

Temperature
Warm ← → Cool94% cool

Reads cool. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.

Luminance by channel
Red2%
Green57%
Blue41%

Green carries most of what the eye calls brightness — that is why WCAG weights it 0.7152.

Every format

HEX#103c9a
HEX (8-digit)#103c9aff
RGBrgb(16, 60, 154)
RGBArgba(16, 60, 154, 1)
HSLhsl(221, 81%, 33%)
HSV / HSBhsv(221, 90%, 60%)
HWBhwb(221 6% 40%)
CMYKcmyk(90%, 61%, 0%, 40%)
LABlab(28.6 23.8 -55.1)
LCHlch(28.6 60.0 293.4)
OKLCHoklch(0.393 0.161 262.6)
XYZ (D65)xyz(7.66, 5.67, 31.26)
Decimal1064090
Display P3color(display-p3 0.063 0.235 0.604)
Web-safe#003399

Copy-ready code

every platformclick to select
/* CSS */
color: #103c9a;
background-color: #103c9a;
/* CSS custom property */
--brand: #103c9a;
/* Tailwind (arbitrary) */
class="text-[#103c9a] bg-[#103c9a]"
/* SCSS */
$brand: #103c9a;
/* SwiftUI */
Color(red: 0.063, green: 0.235, blue: 0.604)
/* UIKit */
UIColor(red: 0.063, green: 0.235, blue: 0.604, alpha: 1)
/* Android XML */
<color name="brand">#103C9A</color>
/* Android Compose */
Color(0xFF103C9A)
/* Flutter */
Color(0xFF103C9A)
/* Python / OpenCV (BGR) */
(154, 60, 16)
/* Python / PIL (RGB) */
(16, 60, 154)
/* Java AWT */
new Color(16, 60, 154)
/* .NET */
Color.FromArgb(255, 16, 60, 154)
/* OpenGL / Unity (0–1) */
(0.0627f, 0.2353f, 0.6039f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{16,60,154}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #103c9a 85%, white);
border-color: color-mix(in oklab, #103c9a 40%, transparent);
/* theme-aware in one line */
color: light-dark(#0C2D74, #D3DBEE);
/* relative colour syntax */
--hover: hsl(from #103c9a h s calc(l - 7));

Design tokens

The same ramp in the four formats a team actually needs. Paste one and the whole palette lands with it.

css custom propertiesclick to select
:root {
  --brand-50: #F3F6FC;
  --brand-100: #E6ECF9;
  --brand-200: #C6D5F6;
  --brand-300: #99B6F4;
  --brand-400: #6792EF;
  --brand-500: #346EEA;
  --brand-600: #1756DE;
  --brand-700: #1348B9;
  --brand-800: #103c9a;
  --brand-900: #0F2D6B;
  --brand-950: #0A1C43;
  --brand: #103c9a;
  --brand-ink: #ffffff;
  --brand-surface: #F4F6FA;
  --brand-border: #C0CEED;
  --brand-hover: #0D2F7A;
  --brand-pressed: #092359;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141924;
    --brand-ink: #D3DBEE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F3F6FC',
        100: '#E6ECF9',
        200: '#C6D5F6',
        300: '#99B6F4',
        400: '#6792EF',
        500: '#346EEA',
        600: '#1756DE',
        700: '#1348B9',
        800: '#103c9a',
        900: '#0F2D6B',
        950: '#0A1C43',
        DEFAULT: '#103c9a',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F3F6FC,
  '100': #E6ECF9,
  '200': #C6D5F6,
  '300': #99B6F4,
  '400': #6792EF,
  '500': #346EEA,
  '600': #1756DE,
  '700': #1348B9,
  '800': #103c9a,
  '900': #0F2D6B,
  '950': #0A1C43,
);
$brand-base: #103c9a;
$brand-ink: #ffffff;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F3F6FC", "$type": "color" },
      "100": { "$value": "#E6ECF9", "$type": "color" },
      "200": { "$value": "#C6D5F6", "$type": "color" },
      "300": { "$value": "#99B6F4", "$type": "color" },
      "400": { "$value": "#6792EF", "$type": "color" },
      "500": { "$value": "#346EEA", "$type": "color" },
      "600": { "$value": "#1756DE", "$type": "color" },
      "700": { "$value": "#1348B9", "$type": "color" },
      "800": { "$value": "#103c9a", "$type": "color" },
      "900": { "$value": "#0F2D6B", "$type": "color" },
      "950": { "$value": "#0A1C43", "$type": "color" }
    },
    "brandInk": { "$value": "#ffffff", "$type": "color" }
  }
}

Best text color

Only one of black and white can be right. This is the one, with the number that proves it.

Readable at a glance#ffffff on #103c9a · 9.84:1
Use #ffffffAAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 9.84:1 · recommended
AA pass · AA large pass · AAA pass
Aa
Black text · 2.13:1
AA fail · AA large fail · AAA fail
Reading the other direction: #103c9a as text scores 9.84:1 on white and 2.13:1 on black.
Best tinted ink on it, if plain black or white feels flat: #E8EEFD at 8.47:1.

Make it accessible

A contrast checker tells you that you failed. This tells you what to ship instead — same hue, same saturation, lightness moved only as far as WCAG demands.

The quick fox
#103c9a · 9.84:1
AA on whitealready passes
#103c9a
The quick fox
#103c9a · 9.84:1
AAA on whitealready passes
#103c9a
The quick fox
#356FEA · 4.61:1
AA on black+23% L
#356FEA
The quick fox
#6893EF · 7.01:1
AAA on black+34% L
#6893EF

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #103C9A is enough for headings on white. Non-text elements such as icons, chart strokes and focus rings also sit at 3:1 under WCAG 2.2 (1.4.11).

Accessibility — WCAG contrast

Aa
#103c9a on white: 9.84:1
AA ✓ pass · AA-large · AAA
Aa
#103c9a on black: 2.13:1
AA ✗ fail · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #103c9a as text on that neutral, and that neutral as text on #103c9a.

NeutralRatioBoth directions
White9.84:1AaAa
Slate 509.40:1AaAa
Slate 1008.98:1AaAa
Slate 2007.98:1AaAa
Slate 3006.62:1AaAa
Slate 4003.84:1AaAa
Slate 5002.07:1AaAa
Slate 6001.30:1AaAa
Slate 7001.05:1AaAa
Slate 8001.49:1AaAa
Slate 9001.82:1AaAa
Black2.13:1AaAa
Colour vision deficiency
true color
protanopia · #004A9D
deuteranopia · #003D98
tritanopia · #005465

Roughly one man in twelve has some form of colour vision deficiency. If any of the three panels above is hard to tell apart from a neighbouring colour in your palette, add a shape, an icon or a label so the meaning does not rest on hue alone.

Color scale — 50 to 950

A Tailwind-shaped ramp built around this exact hex. #103c9a is pinned to step 800; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F3F6FC
#E6ECF9
#C6D5F6
#99B6F4
#6792EF
#346EEA
#1756DE
#1348B9
#103c9a
#0F2D6B
#0A1C43
Base = 800Lightest = 50 · #F3F6FCDarkest = 950 · #0A1C43Text step on white = 500
Perceptual ramp — OKLCH

The same eleven steps expressed in OKLCH, where equal lightness numbers actually look equally spaced. HSL ramps go muddy in the yellows and washed out in the blues; this one does not. Modern browsers render it natively — the hex ramp above is the fallback.

50100200300400500600700800900950
oklch tokensclick to select
:root {
  --brand-50: oklch(0.97 0.040 262.6);
  --brand-100: oklch(0.94 0.064 262.6);
  --brand-200: oklch(0.88 0.096 262.6);
  --brand-300: oklch(0.80 0.125 262.6);
  --brand-400: oklch(0.72 0.148 262.6);
  --brand-500: oklch(0.64 0.161 262.6);
  --brand-600: oklch(0.56 0.161 262.6);
  --brand-700: oklch(0.48 0.151 262.6);
  --brand-800: oklch(0.40 0.135 262.6);
  --brand-900: oklch(0.32 0.113 262.6);
  --brand-950: oklch(0.24 0.088 262.6);
}

Colors that work with #103c9a

Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.

Text on it#ffffff
White wins here
Surface#F4F6FA
Tinted page background
Border#C0CEED
Hairlines and dividers
Muted text#4B649B
Captions on the surface
Accent#9D4B0D
Second voice, not a rival
Dark variant#0C2D74
Hover, pressed, headers
Light variant#E8EEFD
Selected rows, tints
Dark surface#141924
Dark-mode background
Hover#0D2F7A
One step down in lightness
Pressed#092359
Two steps down
Disabled#7484A6
Chroma pulled out
Focus ring#0840B6
Offset from the fill so it reads
Light mode
Everything in its place

Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.

Primary actionSecondaryBadge
Dark mode
Same hue, inverted

Lightness flips, hue holds. The accent stays the anchor in both themes.

Primary actionSecondaryAccent

In real components

The same eight roles, wired into the interface patterns you will actually build with them. Every state below is a computed value, not a mock-up.

Buttons and states
Save changesHoverPressedDisabled
OutlineSubtleLinkFocused
Form field
you@company.com

Focus ring uses the light variant so the field still reads as one shape.

Send me product updates
Notice
Your export is ready

The file stays available for seven days. Download it before it expires.

NewBetaDraft
Data
Storage used68%
Acme LtdActive
NorthwindTrial
GlobexActive

How to use #103c9a

Derived from its contrast, chroma and lightness — not from taste.

Works well for
  • Body text and links on white
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Headers, footers and dark-mode surfaces
  • Brand accents, badges and data highlights
Use with care
  • Text on black or near-black surfaces
  • Full-page backgrounds — tiring over long sessions
  • Black text placed on it
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
Any size
Safe as a fill behind white type
Yes
Safe as a 1px border on white
Yes

Meaning and mood

What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.

trustedcalmcompetentcorporate

The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed.

At this chroma the association is amplified — it will dominate anything placed beside it, so give it space and use it sparingly. The low lightness adds weight and formality.

Worth knowing

It is also the most crowded hue on the web. Distinctiveness has to come from your other choices.

Reads as
  • FormalityHigh
  • EnergyHigh
  • Weight67/100
  • TemperatureCool
  • ApproachabilityReserved

Colour associations are cultural and vary by market. Treat these as a starting point for a conversation with your audience, not a finding about them.

Similar colors

One move away from this hex in each direction. Every swatch is its own page.

Color relationships

The wheel positions with their names attached, so you can grab the one you actually need.

Complementary#9A6E10
Analogous left#10819A
Analogous right#29109A
Split-complement 1#9A2910
Split-complement 2#819A10
Triadic 1#9A103C
Triadic 2#3C9A10
Tetradic#9A1081
On the wheel
Base+30°−30°+120°+240°+180°221°

#103c9a sits at 221°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red6.3%
Green23.5%
Blue60.4%
R · 0–255
16
0x10
G · 0–255
60
0x3c
B · 0–255
154
0x9a

CMYK percentages

Cyan89.6%
Magenta61.0%
Yellow0.0%
Key (black)39.6%

Total ink coverage is 190%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#103c9a text on a black background

contrast 2.13:1

Card sample

#103c9a text on a white background

contrast 9.84:1

Card sample

#103c9a on grey

8.98:1

#103c9a on its own surface

9.09:1

#103c9a on its dark surface

1.79:1

CSS3 live lab

Text font color

The quick brown fox

color: #103c9a;
Background color
Panel with #103c9a background
background-color: #103c9a;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #103c9a;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(16, 60, 154, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(16, 60, 154, 0.45);
Border & gradient
Gradient panel
border: 3px solid #103c9a;
background: linear-gradient(135deg, #103c9a, #40109A);
Gradient text

Gradient headline

background: linear-gradient(90deg, #103c9a, #62109A);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #103c9a;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #103c9a;
caret-color: #103c9a;
Left rule
Pull quote or callout
border-left: 4px solid #103c9a;
Ring + tint
Selected chip
background: #E8EEFD;
box-shadow: inset 0 0 0 2px #103c9a;
Conic badge
68%
background: conic-gradient(#103c9a 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #103c9a over white; the bottom row is the same alpha over a checkerboard, so you can see what survives on a photo or a video.

Bottom row of hexes is the flattened result over white — use those when a design tool refuses transparency, or when you need a solid fallback.

alpha in every syntaxclick to select
rgba(16, 60, 154, 0.5)
rgb(16 60 154 / 50%)
#103c9a80
hsl(221 81% 33% / 50%)
color-mix(in srgb, #103c9a 50%, transparent)
Alpha8-digit hexFlat on white
10%#103c9a1a#E7ECF5
20%#103c9a33#CFD8EB
40%#103c9a66#9FB1D7
60%#103c9a99#708AC2
80%#103c9acc#4063AE

Gradients from #103c9a

Six recipes, each built from this hex and shown with the exact CSS that produced it.

Elevation
Same hue, three lightnesses — safe anywhere
background: linear-gradient(135deg, #1651D1, #103c9a 45%, #0C2D74);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #103c9a, #3E0D7E);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #103c9a, #9A6E10);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #1E5EE8 0%, #103c9a 45%, #0C2D74 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4F6FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #15B6C8 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #3E13B6 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #0C2D74 0%, transparent 65%), #103c9a;

Monochromatic scale

Palettes built from #103c9a

Shades — darker

Tints — lighter

Tones — desaturated

Color harmonies

Nearest named colors

Ranked with CIEDE2000 across all 139 CSS keywords. Under ΔE 2 the eye stops telling them apart; over ΔE 10 they are plainly different colors.

#103c9a in the real world

Where a color in this family tends to land, and the interface roles it is usually asked to play.

Industries
TechnologyFinanceHealthcareEnterprise SaaS
Common UI roles
ButtonsLinksFocus statesCharts
Print note

Sits outside most CMYK gamuts — expect a duller press result, or specify a spot ink.

On screens

Holds up across typical panel gamma. Still worth checking on an uncalibrated laptop, where mid-tones shift most.

In dark mode

Too dim on dark surfaces at 2.13:1 — lift it to #356FEA for body text, or reserve it for fills.

Explore nearby colors

Small, deliberate steps away from this hex — useful when you are hunting for the version of a colour that finally feels right.

#103c9a, answered

What color is #103c9a?

#103c9a is a dark electric blue, closest to Dark Slate Blue (ΔE2000 8). It sits at 221° on the hue wheel with 81% saturation and 33% lightness, which reads as cool.

What is the RGB value of #103c9a?

rgb(16, 60, 154) — 16 red, 60 green and 154 blue out of 255, or 6.3% / 23.5% / 60.4% by channel.

What is #103c9a in HSL and HSV?

hsl(221, 81%, 33%) and hsv(221, 90%, 60%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #103c9a a light or a dark color?

It is a dark color. Relative luminance is 0.0567 and perceived brightness is 27%, so white text on it reaches 9.84:1.

Should I use black or white text on #103c9a?

White. It scores 9.84:1 against #103c9a, versus 2.13:1 for black — AAA at any size.

Is #103c9a accessible on a white background?

#103c9a on white scores 9.84:1, which clears AAA at every size.

What is the complementary color of #103c9a?

#9A6E10 sits directly opposite on the wheel. Softer options are the split-complements #9A2910 and #819A10, which give the same contrast with far less vibration.

What colors go well with #103c9a?

For interface work: #F4F6FA as the surface, #C0CEED for borders, #4B649B for secondary text, #9D4B0D as an accent and #0C2D74 for hover and pressed states. For a palette, the analogous pair #10819A and #29109A stays calm, while #9A6E10 is the loudest partner.

What is #103c9a in CMYK for printing?

cmyk(90%, 61%, 0%, 40%). This is a screen-to-ink approximation — a color this saturated sits outside most CMYK gamuts and will print duller than it looks here.

Is #103c9a warm or cool?

Cool — it scores 94 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #17109A; nudged cooler, #0C3D84.

Which Tailwind color is closest to #103c9a?

The indigo family — its 500 step is #6366f1, ΔE2000 19.4 away. That is a visible difference, so define #103c9a as a custom token rather than reaching for the built-in.

How do I use #103c9a in Tailwind CSS?

Inline it as an arbitrary value with bg-[#103c9a] or text-[#103c9a], or register the whole ramp under theme.extend.colors.brand so you get bg-brand-500 and friends. The generated 50–950 scale on this page is ready to paste into your config.

What is #103c9a with 50% opacity?

rgba(16, 60, 154, 0.5), or #103c9a80 in eight-digit hex. Over white that composites to #889ECD; over black, #081E4D.

Is #103c9a a web-safe color?

No. The nearest web-safe colour is #003399, ΔE2000 2.8 away. The palette only matters for legacy displays and some email clients now.

What does the color #103c9a mean?

As a blue, it reads trusted, calm, competent. The default of institutions for a reason: blue is read as stable and safe across nearly every culture that has been surveyed. At this chroma the effect is amplified — it will dominate whatever sits beside it.

What gradient works with #103c9a?

The safest is same-hue elevation: linear-gradient(135deg, #1651D1, #103c9a 45%, #0C2D74). For more colour, a short hue run to #3E0D7E keeps it rich without turning muddy.

Work with #103c9a in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #103c9a at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.