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blue · cool

#3d9dfb

a balanced, electric blue · cool · closest name: Dodger Blue

Token name suggestion: Atlas Cobalt

RGB
61, 157, 251
HSL
210°, 96%, 61%
CMYK
76, 38, 0, 2
Luminance
0.3207

#3d9dfb is a balanced electric blue, 210° on the wheel and 100/100 on the cool side. Put black text on it (7.41:1). As text it scores 2.83:1 on white — use #0574E2 instead. Nearest name is Dodger Blue, nearest Tailwind family is sky.

hsl(210 96% 61%)rgb(61 157 251)Base step 500AAA inkCool

At a glance

Every number on this page in one read: what #3d9dfb is made of, how bright it looks, and which way it leans.

Hex
#3d9dfb
Hue
210°
blue
Saturation
96%
electric
Lightness
61%
balanced
Brightness
98%
HSV value
Perceived
59%
weighted brightness
Luminance
0.3207
WCAG relative
Temperature
Cool
100/100 cool
Color family
Blue
Tone
Electric
Best ink
Black
7.41:1
Closest name
Dodger Blue
ΔE2000 4
Chroma
54.8
LCH, 0–130ish
OKLCH L
0.684
perceptual lightness
Tailwind
sky
500 · ΔE 7.2
Web-safe
#3399FF
nearest of 216
Where it sits
Hue210° of 360°
Saturation96%
Lightness61%
Saturation × lightness field

Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #3d9dfb.

Temperature
Warm ← → Cool100% 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
Red3%
Green75%
Blue22%

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

Every format

HEX#3d9dfb
HEX (8-digit)#3d9dfbff
RGBrgb(61, 157, 251)
RGBArgba(61, 157, 251, 1)
HSLhsl(210, 96%, 61%)
HSV / HSBhsv(210, 76%, 98%)
HWBhwb(210 24% 2%)
CMYKcmyk(76%, 38%, 0%, 2%)
LABlab(63.4 3.4 -54.7)
LCHlch(63.4 54.8 273.5)
OKLCHoklch(0.684 0.165 251.2)
XYZ (D65)xyz(31.39, 32.07, 95.78)
Decimal4038139
Display P3color(display-p3 0.239 0.616 0.984)
Web-safe#3399FF

Copy-ready code

every platformclick to select
/* CSS */
color: #3d9dfb;
background-color: #3d9dfb;
/* CSS custom property */
--brand: #3d9dfb;
/* Tailwind (arbitrary) */
class="text-[#3d9dfb] bg-[#3d9dfb]"
/* SCSS */
$brand: #3d9dfb;
/* SwiftUI */
Color(red: 0.239, green: 0.616, blue: 0.984)
/* UIKit */
UIColor(red: 0.239, green: 0.616, blue: 0.984, alpha: 1)
/* Android XML */
<color name="brand">#3D9DFB</color>
/* Android Compose */
Color(0xFF3D9DFB)
/* Flutter */
Color(0xFF3D9DFB)
/* Python / OpenCV (BGR) */
(251, 157, 61)
/* Python / PIL (RGB) */
(61, 157, 251)
/* Java AWT */
new Color(61, 157, 251)
/* .NET */
Color.FromArgb(255, 61, 157, 251)
/* OpenGL / Unity (0–1) */
(0.2392f, 0.6157f, 0.9843f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{61,157,251}
modern cssclick to select
/* mix without leaving CSS */
background: color-mix(in oklab, #3d9dfb 85%, white);
border-color: color-mix(in oklab, #3d9dfb 40%, transparent);
/* theme-aware in one line */
color: light-dark(#03407D, #D3E1EE);
/* relative colour syntax */
--hover: hsl(from #3d9dfb 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: #F1F7FD;
  --brand-100: #E4F0FC;
  --brand-200: #C1DEFA;
  --brand-300: #91C7FD;
  --brand-400: #5AACFC;
  --brand-500: #3d9dfb;
  --brand-600: #057CF0;
  --brand-700: #0467C8;
  --brand-800: #0352A0;
  --brand-900: #073E73;
  --brand-950: #042748;
  --brand: #3d9dfb;
  --brand-ink: #000000;
  --brand-surface: #F4F7FA;
  --brand-border: #C0D6ED;
  --brand-hover: #1A8BFA;
  --brand-pressed: #057AEC;
}
@media (prefers-color-scheme: dark) {
  :root {
    --brand-surface: #141C24;
    --brand-ink: #D3E1EE;
  }
}
tailwind.config.jsclick to select
theme: {
  extend: {
    colors: {
      brand: {
        50: '#F1F7FD',
        100: '#E4F0FC',
        200: '#C1DEFA',
        300: '#91C7FD',
        400: '#5AACFC',
        500: '#3d9dfb',
        600: '#057CF0',
        700: '#0467C8',
        800: '#0352A0',
        900: '#073E73',
        950: '#042748',
        DEFAULT: '#3d9dfb',
      },
    },
  },
}
scss mapclick to select
$brand: (
  '50': #F1F7FD,
  '100': #E4F0FC,
  '200': #C1DEFA,
  '300': #91C7FD,
  '400': #5AACFC,
  '500': #3d9dfb,
  '600': #057CF0,
  '700': #0467C8,
  '800': #0352A0,
  '900': #073E73,
  '950': #042748,
);
$brand-base: #3d9dfb;
$brand-ink: #000000;

@function brand($step) { @return map-get($brand, $step); }
w3c design tokens (json)click to select
{
  "color": {
    "brand": {
      "50": { "$value": "#F1F7FD", "$type": "color" },
      "100": { "$value": "#E4F0FC", "$type": "color" },
      "200": { "$value": "#C1DEFA", "$type": "color" },
      "300": { "$value": "#91C7FD", "$type": "color" },
      "400": { "$value": "#5AACFC", "$type": "color" },
      "500": { "$value": "#3d9dfb", "$type": "color" },
      "600": { "$value": "#057CF0", "$type": "color" },
      "700": { "$value": "#0467C8", "$type": "color" },
      "800": { "$value": "#0352A0", "$type": "color" },
      "900": { "$value": "#073E73", "$type": "color" },
      "950": { "$value": "#042748", "$type": "color" }
    },
    "brandInk": { "$value": "#000000", "$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#000000 on #3d9dfb · 7.41:1
Use #000000AAA at every size.
Aa
12px
Aa
16px
Aa
24px
Aa
White text · 2.83:1
AA fail · AA large fail · AAA fail
Aa
Black text · 7.41:1 · recommended
AA pass · AA large pass · AAA pass
Reading the other direction: #3d9dfb as text scores 2.83:1 on white and 7.41:1 on black.
Best tinted ink on it, if plain black or white feels flat: #03407D at 3.65:1.

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
#0574E2 · 4.56:1
AA on white−16% L
#0574E2
The quick fox
#0358AB · 7.03:1
AAA on white−27% L
#0358AB
The quick fox
#3d9dfb · 7.41:1
AA on blackalready passes
#3d9dfb
The quick fox
#3d9dfb · 7.41:1
AAA on blackalready passes
#3d9dfb

Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #2E95FB 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
#3d9dfb on white: 2.83:1
AA ✗ fail · AA-large · AAA
Aa
#3d9dfb on black: 7.41:1
AA ✓ pass · AA-large · AAA
Against the neutral ladder

Contrast is symmetric, so each row covers both directions: #3d9dfb as text on that neutral, and that neutral as text on #3d9dfb.

NeutralRatioBoth directions
White2.83:1AaAa
Slate 502.71:1AaAa
Slate 1002.59:1AaAa
Slate 2002.30:1AaAa
Slate 3001.91:1AaAa
Slate 4001.10:1AaAa
Slate 5001.68:1AaAa
Slate 6002.68:1AaAa
Slate 7003.66:1AaAa
Slate 8005.16:1AaAa
Slate 9006.30:1AaAa
Black7.41:1AaAa
Colour vision deficiency
true color
protanopia · #71A3FF
deuteranopia · #5392F9
tritanopia · #00B3C0

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. #3d9dfb is pinned to step 500; the rest hold its hue and let saturation ease off at the extremes so the pale end never turns neon.

#F1F7FD
#E4F0FC
#C1DEFA
#91C7FD
#5AACFC
#3d9dfb
#057CF0
#0467C8
#0352A0
#073E73
#042748
Base = 500Lightest = 50 · #F1F7FDDarkest = 950 · #042748Text step on white = 700
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 0.041 251.2);
  --brand-100: oklch(0.94 0.066 251.2);
  --brand-200: oklch(0.88 0.099 251.2);
  --brand-300: oklch(0.80 0.129 251.2);
  --brand-400: oklch(0.72 0.152 251.2);
  --brand-500: oklch(0.64 0.165 251.2);
  --brand-600: oklch(0.56 0.165 251.2);
  --brand-700: oklch(0.48 0.155 251.2);
  --brand-800: oklch(0.40 0.139 251.2);
  --brand-900: oklch(0.32 0.115 251.2);
  --brand-950: oklch(0.24 0.091 251.2);
}

Colors that work with #3d9dfb

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

Text on it#000000
Black wins here
Surface#F4F7FA
Tinted page background
Border#C0D6ED
Hairlines and dividers
Muted text#4B739B
Captions on the surface
Accent#CC3200
Second voice, not a rival
Dark variant#03407D
Hover, pressed, headers
Light variant#E6F2FE
Selected rows, tints
Dark surface#141C24
Dark-mode background
Hover#1A8BFA
One step down in lightness
Pressed#057AEC
Two steps down
Disabled#CBD4DE
Chroma pulled out
Focus ring#4EA7FF
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 #3d9dfb

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

Works well for
  • Text and icons on dark surfaces
  • Primary buttons and calls to action
  • Focus rings, active and selected states
  • Brand accents, badges and data highlights
  • Chart series and data categories
Use with care
  • Text of any size on white — fails WCAG AA
  • Full-page backgrounds — tiring over long sessions
  • Pairing with a same-lightness hue — edges vibrate
Minimum size as text on white
Not as text
Safe as a fill behind white type
No — use #03407D
Safe as a 1px border on white
No — use #2E95FB

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 mid lightness keeps it versatile in both themes.

Worth knowing

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

Reads as
  • FormalityLow
  • EnergyHigh
  • Weight39/100
  • 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#FB9B3D
Analogous left#3DFBFA
Analogous right#3D3EFB
Split-complement 1#FB3D3E
Split-complement 2#FBFA3D
Triadic 1#FB3D9D
Triadic 2#9DFB3D
Tetradic#FA3DFB
On the wheel
Base+30°−30°+120°+240°+180°210°

#3d9dfb sits at 210°. Every dot is a harmony position and links to its own page in the table alongside.

RGB percentages

Red23.9%
Green61.6%
Blue98.4%
R · 0–255
61
0x3d
G · 0–255
157
0x9d
B · 0–255
251
0xfb

CMYK percentages

Cyan75.7%
Magenta37.5%
Yellow0.0%
Key (black)1.6%

Total ink coverage is 115%. Most commercial presses cap around 300% — above that, sheets stop drying properly.

Color previews

#3d9dfb text on a black background

contrast 7.41:1

Card sample

#3d9dfb text on a white background

contrast 2.83:1

Card sample

#3d9dfb on grey

2.59:1

#3d9dfb on its own surface

2.63:1

#3d9dfb on its dark surface

6.07:1

CSS3 live lab

Text font color

The quick brown fox

color: #3d9dfb;
Background color
Panel with #3d9dfb background
background-color: #3d9dfb;
Text shadow — hex

Glowing headline

text-shadow: 2px 2px 8px #3d9dfb;
Text shadow — RGB

Soft neon halo

text-shadow: 0 0 14px rgba(61, 157, 251, 0.45);
Div box shadow
Elevated card
box-shadow: 0 12px 32px -8px rgba(61, 157, 251, 0.45);
Border & gradient
Gradient panel
border: 3px solid #3d9dfb;
background: linear-gradient(135deg, #3d9dfb, #5C3DFB);
Gradient text

Gradient headline

background: linear-gradient(90deg, #3d9dfb, #8B3DFB);
-webkit-background-clip: text;
color: transparent;
Focus ring
Focused control
outline: 2px solid #3d9dfb;
outline-offset: 3px;
Underline & caret

Marked up text

text-decoration-color: #3d9dfb;
caret-color: #3d9dfb;
Left rule
Pull quote or callout
border-left: 4px solid #3d9dfb;
Ring + tint
Selected chip
background: #E6F2FE;
box-shadow: inset 0 0 0 2px #3d9dfb;
Conic badge
68%
background: conic-gradient(#3d9dfb 68%, #e2e8f0 0);

Transparency

What each alpha value actually composites to. The top row is #3d9dfb 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(61, 157, 251, 0.5)
rgb(61 157 251 / 50%)
#3d9dfb80
hsl(210 96% 61% / 50%)
color-mix(in srgb, #3d9dfb 50%, transparent)
Alpha8-digit hexFlat on white
10%#3d9dfb1a#ECF5FF
20%#3d9dfb33#D8EBFE
40%#3d9dfb66#B1D8FD
60%#3d9dfb99#8BC4FD
80%#3d9dfbcc#64B1FC

Gradients from #3d9dfb

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, #79BBFC, #3d9dfb 45%, #03407D);
Duotone
A short hue run reads richer than a flat fill
background: linear-gradient(120deg, #3d9dfb, #551FFA);
Complement sweep
Loud — keep it behind large type only
background: linear-gradient(90deg, #3d9dfb, #FB9B3D);
Spotlight
Hero panels and app headers
background: radial-gradient(120% 120% at 20% 0%, #97CAFD 0%, #3d9dfb 45%, #03407D 100%);
Soft wash
Section backgrounds that stay readable
background: linear-gradient(180deg, #F4F7FA, #ffffff);
Mesh
Ambient background, no image weight
background: radial-gradient(60% 60% at 15% 20%, #6FFCF0 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #685BFC 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #03407D 0%, transparent 65%), #3d9dfb;

Monochromatic scale

Palettes built from #3d9dfb

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.

#3d9dfb 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

Usable as-is on a dark surface at 7.41:1.

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.

#3d9dfb, answered

What color is #3d9dfb?

#3d9dfb is a balanced electric blue, closest to Dodger Blue (ΔE2000 4). It sits at 210° on the hue wheel with 96% saturation and 61% lightness, which reads as cool.

What is the RGB value of #3d9dfb?

rgb(61, 157, 251) — 61 red, 157 green and 251 blue out of 255, or 23.9% / 61.6% / 98.4% by channel.

What is #3d9dfb in HSL and HSV?

hsl(210, 96%, 61%) and hsv(210, 76%, 98%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.

Is #3d9dfb a light or a dark color?

It is a mid-tone. Relative luminance is 0.3207 and perceived brightness is 59%, so black text on it reaches 7.41:1.

Should I use black or white text on #3d9dfb?

Black. It scores 7.41:1 against #3d9dfb, versus 2.83:1 for white — AAA at any size.

Is #3d9dfb accessible on a white background?

#3d9dfb on white scores 2.83:1, which fails WCAG AA at every size. Darken it to #0574E2 to reach 4.5:1, or #0358AB for 7:1.

What is the complementary color of #3d9dfb?

#FB9B3D sits directly opposite on the wheel. Softer options are the split-complements #FB3D3E and #FBFA3D, which give the same contrast with far less vibration.

What colors go well with #3d9dfb?

For interface work: #F4F7FA as the surface, #C0D6ED for borders, #4B739B for secondary text, #CC3200 as an accent and #03407D for hover and pressed states. For a palette, the analogous pair #3DFBFA and #3D3EFB stays calm, while #FB9B3D is the loudest partner.

What is #3d9dfb in CMYK for printing?

cmyk(76%, 38%, 0%, 2%). 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 #3d9dfb warm or cool?

Cool — it scores 100 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #3D57FB; nudged cooler, #228DFD.

Which Tailwind color is closest to #3d9dfb?

The sky family — its 500 step is #0ea5e9, ΔE2000 7.2 away. That is a visible difference, so define #3d9dfb as a custom token rather than reaching for the built-in.

How do I use #3d9dfb in Tailwind CSS?

Inline it as an arbitrary value with bg-[#3d9dfb] or text-[#3d9dfb], 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 #3d9dfb with 50% opacity?

rgba(61, 157, 251, 0.5), or #3d9dfb80 in eight-digit hex. Over white that composites to #9ECEFD; over black, #1F4F7E.

Is #3d9dfb a web-safe color?

No. The nearest web-safe colour is #3399FF, ΔE2000 1.3 away. The palette only matters for legacy displays and some email clients now.

What does the color #3d9dfb 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 #3d9dfb?

The safest is same-hue elevation: linear-gradient(135deg, #79BBFC, #3d9dfb 45%, #03407D). For more colour, a short hue run to #551FFA keeps it rich without turning muddy.

Work with #3d9dfb in the Color Lab

Every tool opens with this colour already loaded.

Every value on this page is computed from #3d9dfb at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.