Conversions, palettes, contrast & design ideas for this color.
Color profile
#AC0500 is a warm color from the Red family, closest in name to “Heartbeat”. In RGB it is rgb(172, 5, 0); in HSL, hsl(2, 100%, 34%).
The color Heartbeat, with hexadecimal code #ac0500, falls within the red color family, a hue strongly linked to passion, urgency, and primal energy. Across cultures, red ranges from the luck of Chinese New Year to the romance of Western Valentine's Day. Additionally, it evokes emotions such as Passion, Energy, Love, Excitement, Danger and Desire. In many Eastern cultures, red symbolizes luck, prosperity, and happiness, often used in festivals and weddings. In Western cultures, red can symbolize passion, love, and sometimes danger. With a high saturation of 100%, this color is intensely vivid—demanding attention and ideal for focal elements like buttons, banners, and brand marks. Its low lightness of 34% produces a deep, rich appearance—conveying gravity and luxury, particularly effective in dark-mode designs and premium packaging. This color is ideal for designs that aim to express Passion, Energy, Love, Excitement, Danger, or Desire. It can be effectively used in web design, branding, and marketing materials to attract attention and convey specific messages.
Key facts
The story of this color
Heartbeat (#AC0500) belongs to the Red color family.
This deep, saturated shade conveys authority and richness. Deep tones are favored in luxury packaging, evening-event branding, and dark-mode interfaces where they provide dramatic contrast against lighter elements.
Red ochre is among the earliest pigments used by humans, found in cave paintings over 40,000 years old. The precious cochineal dye—extracted from scale insects—was so valuable in colonial-era trade that it rivaled gold. In imperial China, vermilion lacquer adorned thrones and temples, while Roman generals painted their faces red for triumphal processions through the streets of Rome.
Red commands instant attention, making it the top choice for call-to-action buttons, sale banners, and emergency signage. Use it selectively to avoid overwhelming users—pair red accents with neutral backgrounds (white, light gray, or cream) to create high-impact focal points that guide the eye without fatigue.
Positioned on the warm side of the color wheel (hue 2°), it naturally draws the eye and creates a sense of closeness—making it effective for calls to action, food photography, and hospitality branding. At 100% saturation, this is a highly vivid color that demands attention. Use it where maximum visual impact is needed—feature banners, accent buttons, and data-visualization highlights.
Red accelerates heart rate and triggers primal alertness, linking it to passion, urgency, and excitement. In marketing, red increases impulse buying; in UX, red signals errors or critical states. Culturally, red spans love (Western Valentine's Day) and luck (Chinese New Year).
Its low lightness of 34% gives it a deep, intense presence. Deep tones like this excel as dark-mode backgrounds, header bars, and anywhere a sense of gravity or luxury is desired.
Combine a rich crimson with gold foil for luxury packaging. In web design, use a single red accent button on a monochrome page for maximum conversion impact. For sports branding, pair red with black and white for aggressive, high-energy team identities.
Every format
Every way to write Heartbeat — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#AC0500
Hexadecimal is the web’s universal color notation — two digits each for red, green and blue. Drop it straight into HTML, CSS or any design tool.
rgb(172, 5, 0)
RGB is the additive Red-Green-Blue model every screen uses to emit light. The default choice for websites, apps and on-screen UI.
hsl(2, 100%, 34%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(2, 100%, 67%)
HSV (also called HSB) maps Hue, Saturation and Value/Brightness. It is the model behind the color pickers in Photoshop, Figma and most design apps.
hwb(2 0% 33%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(0%, 97%, 100%, 33%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(46.90% 0.190 29.60)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(46.90% 0.165 0.094)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 35.75, a: 59.02, b: 49.99
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 35.75, C: 77.35, H: 40.26
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 17.07, Y: 8.88, Z: 0.81
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
11273472
The 24-bit integer value of the color — handy for databases, APIs, game engines and low-level graphics code.
Channel breakdown
How much red, green and blue light mixes into Heartbeat.
Percentages show each channel's share of the total light (R + G + B) in Heartbeat.
Ink coverage
Ink needed to reproduce Heartbeat in four-color print. Heaviest ink: Yellow.
Print tip: treat these values as a starting point — final output depends on printer profile, paper stock and calibration.
Accessibility · WCAG
How bright Heartbeat is, and how far black and white text clear each WCAG bar.
Contrast ratio · 1:1 → 21:1 (log scale)
Developer shortcuts
Copy-and-paste CSS for Heartbeat — per-line copy, or grab the whole block.
background-color: #AC0500;
color: #AC0500;
border: 2px solid #AC0500;
background-color: rgb(172, 5, 0);
background-color: hsl(2, 100%, 34%);
--color: #AC0500;
Shades · light to dark
Lighter and darker steps of Heartbeat — the color's full brightness range in one strip.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 180° apart
Two colors opposite on the wheel — maximum contrast for attention-grabbing accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · adjacent hues
Neighboring hues on the wheel — harmonious, calm combinations that feel unified.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 120° apart
Three colors evenly spaced on the wheel — vibrant and energetic, yet balanced.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 90° apart
Four colors evenly spaced on the wheel (tetradic) — rich schemes with multiple accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Accessibility
How Heartbeat reads across five kinds of color vision — a ✓ Friendly verdict means the color difference stays distinguishable for that vision type.
The dot marks the original color. Hover any shade to copy its hex.
Harmony overview
The lead color from each harmony scheme, side by side — a shortcut to the full palettes above.
Perceptually nearby
A step away in brightness, richness or shade — each still feels like the same color.
From the color-name library
The closest named colors to #AC0500 — same mood, each with its own character.
Looking for more Red shades? Browse Red colors →
Inspiration
Curated Unsplash photos that carry the mood of Heartbeat — hover any tile to download it or view the original.
Good to know
Harmony