#f03521
a balanced, electric red · warm · closest name: Red
Token name suggestion: Studio Cardinal
#f03521 is a balanced electric red, 6° on the wheel and 13/100 on the cool side. Put black text on it (5.24:1). As text it scores 4.01:1 on white — large text only. Nearest name is Red, nearest Tailwind family is red.
At a glance
Every number on this page in one read: what #f03521 is made of, how bright it looks, and which way it leans.
Left edge is grey, right edge is full chroma; top is white, bottom is black. The dot is #f03521.
Reads warm. Warm and cool siblings keep the same lightness, so you can swap one in without redoing your contrast maths.
Green carries most of what the eye calls brightness — that is why WCAG weights it 0.7152.
Every format
| HEX | #f03521 |
| HEX (8-digit) | #f03521ff |
| RGB | rgb(240, 53, 33) |
| RGBA | rgba(240, 53, 33, 1) |
| HSL | hsl(6, 87%, 54%) |
| HSV / HSB | hsv(6, 86%, 94%) |
| HWB | hwb(6 13% 6%) |
| CMYK | cmyk(0%, 78%, 86%, 6%) |
| LAB | lab(53.1 68.6 55.3) |
| LCH | lch(53.1 88.1 38.9) |
| OKLCH | oklch(0.623 0.224 30.4) |
| XYZ (D65) | xyz(37.49, 21.19, 3.55) |
| Decimal | 15742241 |
| Display P3 | color(display-p3 0.941 0.208 0.129) |
| Web-safe | #FF3333 |
Copy-ready code
/* CSS */
color: #f03521;
background-color: #f03521;
/* CSS custom property */
--brand: #f03521;
/* Tailwind (arbitrary) */
class="text-[#f03521] bg-[#f03521]"
/* SCSS */
$brand: #f03521;
/* SwiftUI */
Color(red: 0.941, green: 0.208, blue: 0.129)
/* UIKit */
UIColor(red: 0.941, green: 0.208, blue: 0.129, alpha: 1)
/* Android XML */
<color name="brand">#F03521</color>
/* Android Compose */
Color(0xFFF03521)
/* Flutter */
Color(0xFFF03521)
/* Python / OpenCV (BGR) */
(33, 53, 240)
/* Python / PIL (RGB) */
(240, 53, 33)
/* Java AWT */
new Color(240, 53, 33)
/* .NET */
Color.FromArgb(255, 240, 53, 33)
/* OpenGL / Unity (0–1) */
(0.9412f, 0.2078f, 0.1294f, 1f)
/* LaTeX */
\definecolor{brand}{RGB}{240,53,33}/* mix without leaving CSS */ background: color-mix(in oklab, #f03521 85%, white); border-color: color-mix(in oklab, #f03521 40%, transparent); /* theme-aware in one line */ color: light-dark(#771308, #EED5D3); /* relative colour syntax */ --hover: hsl(from #f03521 h s calc(l - 7));
Design tokens
The same ramp in the four formats a team actually needs. Paste one and the whole palette lands with it.
:root {
--brand-50: #FDF3F2;
--brand-100: #FAE7E5;
--brand-200: #F7C9C4;
--brand-300: #F89F96;
--brand-400: #F47061;
--brand-500: #f03521;
--brand-600: #E52410;
--brand-700: #BF1E0D;
--brand-800: #99180A;
--brand-900: #6E160C;
--brand-950: #450D08;
--brand: #f03521;
--brand-ink: #000000;
--brand-surface: #FAF5F4;
--brand-border: #EDC4C0;
--brand-hover: #DE230F;
--brand-pressed: #BD1E0D;
}
@media (prefers-color-scheme: dark) {
:root {
--brand-surface: #241514;
--brand-ink: #EED5D3;
}
}theme: {
extend: {
colors: {
brand: {
50: '#FDF3F2',
100: '#FAE7E5',
200: '#F7C9C4',
300: '#F89F96',
400: '#F47061',
500: '#f03521',
600: '#E52410',
700: '#BF1E0D',
800: '#99180A',
900: '#6E160C',
950: '#450D08',
DEFAULT: '#f03521',
},
},
},
}$brand: (
'50': #FDF3F2,
'100': #FAE7E5,
'200': #F7C9C4,
'300': #F89F96,
'400': #F47061,
'500': #f03521,
'600': #E52410,
'700': #BF1E0D,
'800': #99180A,
'900': #6E160C,
'950': #450D08,
);
$brand-base: #f03521;
$brand-ink: #000000;
@function brand($step) { @return map-get($brand, $step); }{
"color": {
"brand": {
"50": { "$value": "#FDF3F2", "$type": "color" },
"100": { "$value": "#FAE7E5", "$type": "color" },
"200": { "$value": "#F7C9C4", "$type": "color" },
"300": { "$value": "#F89F96", "$type": "color" },
"400": { "$value": "#F47061", "$type": "color" },
"500": { "$value": "#f03521", "$type": "color" },
"600": { "$value": "#E52410", "$type": "color" },
"700": { "$value": "#BF1E0D", "$type": "color" },
"800": { "$value": "#99180A", "$type": "color" },
"900": { "$value": "#6E160C", "$type": "color" },
"950": { "$value": "#450D08", "$type": "color" }
},
"brandInk": { "$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.
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.
Large text — 24px regular or 18.66px bold and above — only needs 3:1, so #F03521 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
Contrast is symmetric, so each row covers both directions: #f03521 as text on that neutral, and that neutral as text on #f03521.
| Neutral | Ratio | Verdict | Both directions |
|---|---|---|---|
| White#ffffff | 4.01:1 | AAAA lgAAA | AaAa |
| Slate 50#f8fafc | 3.83:1 | AAAA lgAAA | AaAa |
| Slate 100#f1f5f9 | 3.66:1 | AAAA lgAAA | AaAa |
| Slate 200#e2e8f0 | 3.25:1 | AAAA lgAAA | AaAa |
| Slate 300#cbd5e1 | 2.70:1 | AAAA lgAAA | AaAa |
| Slate 400#94a3b8 | 1.56:1 | AAAA lgAAA | AaAa |
| Slate 500#64748b | 1.19:1 | AAAA lgAAA | AaAa |
| Slate 600#475569 | 1.89:1 | AAAA lgAAA | AaAa |
| Slate 700#334155 | 2.58:1 | AAAA lgAAA | AaAa |
| Slate 800#1e293b | 3.65:1 | AAAA lgAAA | AaAa |
| Slate 900#0f172a | 4.45:1 | AAAA lgAAA | AaAa |
| Black#000000 | 5.24:1 | AAAA lgAAA | AaAa |
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. #f03521 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.
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.
:root {
--brand-50: oklch(0.97 0.056 30.4);
--brand-100: oklch(0.94 0.090 30.4);
--brand-200: oklch(0.88 0.135 30.4);
--brand-300: oklch(0.80 0.175 30.4);
--brand-400: oklch(0.72 0.206 30.4);
--brand-500: oklch(0.64 0.224 30.4);
--brand-600: oklch(0.56 0.224 30.4);
--brand-700: oklch(0.48 0.211 30.4);
--brand-800: oklch(0.40 0.188 30.4);
--brand-900: oklch(0.32 0.157 30.4);
--brand-950: oklch(0.24 0.123 30.4);
}Colors that work with #f03521
Not a palette — a role sheet. Each swatch answers one question you will hit while building the component.
Surface, border, heading and body all derive from this one hue, so the screen stays coherent without a second palette.
Lightness flips, hue holds. The accent stays the anchor in both themes.
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.
Focus ring uses the light variant so the field still reads as one shape.
The file stays available for seven days. Download it before it expires.
How to use #f03521
Derived from its contrast, chroma and lightness — not from taste.
- ✓Headings from 24px up on white
- ✓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
- ⚠Small text on white — under 4.5:1
- ⚠Full-page backgrounds — tiring over long sessions
- ⚠Status meaning — pair it with an icon or label, never colour alone
- ⚠Pairing with a same-lightness hue — edges vibrate
Meaning and mood
What a colour in this family tends to signal, and how this particular chroma and lightness change the reading.
Red arrives before the rest of the page does. It raises attention and appetite, which is why it runs food, sport and clearance pricing.
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.
It is also the universal error colour. Use it as a brand accent and users may read a warning that is not there.
- FormalityLow
- EnergyHigh
- Weight47/100
- TemperatureWarm
- ApproachabilityHigh
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 | #21DCF0 | Directly opposite — maximum tension | |
| Analogous left | #F02174 | Neighbour, quieter | |
| Analogous right | #F09C21 | Neighbour, quieter | |
| Split-complement 1 | #21F09C | Contrast without the clash | |
| Split-complement 2 | #2174F0 | Contrast without the clash | |
| Triadic 1 | #21F035 | Even thirds — balanced and loud | |
| Triadic 2 | #3521F0 | Even thirds — balanced and loud | |
| Tetradic | #74F021 | Fourth corner of the square scheme |
#f03521 sits at 6°. Every dot is a harmony position and links to its own page in the table alongside.
RGB percentages
CMYK percentages
Total ink coverage is 170%. Most commercial presses cap around 300% — above that, sheets stop drying properly.
Color previews
#f03521 text on a black background
contrast 5.24:1
#f03521 text on a white background
contrast 4.01:1
#f03521 on grey
3.66:1
#f03521 on its own surface
3.71:1
#f03521 on its dark surface
4.39:1
CSS3 live lab
The quick brown fox
color: #f03521;
background-color: #f03521;
Glowing headline
text-shadow: 2px 2px 8px #f03521;
Soft neon halo
text-shadow: 0 0 14px rgba(240, 53, 33, 0.45);
box-shadow: 0 12px 32px -8px rgba(240, 53, 33, 0.45);
border: 3px solid #f03521; background: linear-gradient(135deg, #f03521, #F0BF21);
Gradient headline
background: linear-gradient(90deg, #f03521, #EDF021); -webkit-background-clip: text; color: transparent;
outline: 2px solid #f03521; outline-offset: 3px;
Marked up text
text-decoration-color: #f03521; caret-color: #f03521;
border-left: 4px solid #f03521;
background: #FDE9E7; box-shadow: inset 0 0 0 2px #f03521;
background: conic-gradient(#f03521 68%, #e2e8f0 0);
Transparency
What each alpha value actually composites to. The top row is #f03521 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.
rgba(240, 53, 33, 0.5) rgb(240 53 33 / 50%) #f0352180 hsl(6 87% 54% / 50%) color-mix(in srgb, #f03521 50%, transparent)
| Alpha | 8-digit hex | Flat on white |
|---|---|---|
| 10% | #f035211a | #FEEBE9 |
| 20% | #f0352133 | #FCD7D3 |
| 40% | #f0352166 | #F9AEA6 |
| 60% | #f0352199 | #F6867A |
| 80% | #f03521cc | #F35D4D |
Gradients from #f03521
Six recipes, each built from this hex and shown with the exact CSS that produced it.
background: linear-gradient(135deg, #F4695A, #f03521 45%, #771308);
background: linear-gradient(120deg, #f03521, #E3C20F);
background: linear-gradient(90deg, #f03521, #21DCF0);
background: radial-gradient(120% 120% at 20% 0%, #F68377 0%, #f03521 45%, #771308 100%);
background: linear-gradient(180deg, #FAF5F4, #ffffff);
background: radial-gradient(60% 60% at 15% 20%, #F351A0 0%, transparent 60%), radial-gradient(55% 55% at 85% 15%, #F2B83E 0%, transparent 60%), radial-gradient(70% 70% at 50% 95%, #771308 0%, transparent 65%), #f03521;
Monochromatic scale
Palettes built from #f03521
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.
Closest color with a full write-up: Coca-Cola Red (#f40009) — ΔE2000 3.1 away, with its history, psychology and brand usage.
#f03521 in the real world
Where a color in this family tends to land, and the interface roles it is usually asked to play.
Sits outside most CMYK gamuts — expect a duller press result, or specify a spot ink.
Holds up across typical panel gamma. Still worth checking on an uncalibrated laptop, where mid-tones shift most.
Usable as-is on a dark surface at 5.24:1.
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.
#f03521, answered
What color is #f03521?
#f03521 is a balanced electric red, closest to Red (ΔE2000 3.2). It sits at 6° on the hue wheel with 87% saturation and 54% lightness, which reads as warm.
What is the RGB value of #f03521?
rgb(240, 53, 33) — 240 red, 53 green and 33 blue out of 255, or 94.1% / 20.8% / 12.9% by channel.
What is #f03521 in HSL and HSV?
hsl(6, 87%, 54%) and hsv(6, 86%, 94%). HSL is what CSS takes; HSV is what your design tool's picker shows, which is why the saturation numbers rarely match.
Is #f03521 a light or a dark color?
It is a mid-tone. Relative luminance is 0.2118 and perceived brightness is 54%, so black text on it reaches 5.24:1.
Should I use black or white text on #f03521?
Black. It scores 5.24:1 against #f03521, versus 4.01:1 for white — AA at any size.
Is #f03521 accessible on a white background?
#f03521 on white scores 4.01:1, which only clears AA for large text — 18.66px bold or 24px regular and up. Darken it to #E3240F to reach 4.5:1, or #AE1C0C for 7:1.
What is the complementary color of #f03521?
#21DCF0 sits directly opposite on the wheel. Softer options are the split-complements #21F09C and #2174F0, which give the same contrast with far less vibration.
What colors go well with #f03521?
For interface work: #FAF5F4 as the surface, #EDC4C0 for borders, #9B524B for secondary text, #09C3A6 as an accent and #771308 for hover and pressed states. For a palette, the analogous pair #F02174 and #F09C21 stays calm, while #21DCF0 is the loudest partner.
What is #f03521 in CMYK for printing?
cmyk(0%, 78%, 86%, 6%). 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 #f03521 warm or cool?
Warm — it scores 13 on a scale where 0 is the warmest orange and 100 the coolest azure. Nudged warmer it becomes #F05921; nudged cooler, #F21F58.
Which Tailwind color is closest to #f03521?
The red family — its 500 step is #ef4444, ΔE2000 6.5 away. That is a visible difference, so define #f03521 as a custom token rather than reaching for the built-in.
How do I use #f03521 in Tailwind CSS?
Inline it as an arbitrary value with bg-[#f03521] or text-[#f03521], 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 #f03521 with 50% opacity?
rgba(240, 53, 33, 0.5), or #f0352180 in eight-digit hex. Over white that composites to #F89A90; over black, #781B11.
Is #f03521 a web-safe color?
No. The nearest web-safe colour is #FF3333, ΔE2000 4.5 away. The palette only matters for legacy displays and some email clients now.
What does the color #f03521 mean?
As a red, it reads urgent, appetising, bold. Red arrives before the rest of the page does. It raises attention and appetite, which is why it runs food, sport and clearance pricing. At this chroma the effect is amplified — it will dominate whatever sits beside it.
What gradient works with #f03521?
The safest is same-hue elevation: linear-gradient(135deg, #F4695A, #f03521 45%, #771308). For more colour, a short hue run to #E3C20F keeps it rich without turning muddy.
Work with #f03521 in the Color Lab
Every tool opens with this colour already loaded.
Every value on this page is computed from #f03521 at request time — conversions, contrast ratios and ΔE distances are calculated, never looked up.