Color #B51C1C Color / Colour Code #B51C1C
This page shows the hex color code for color #b51c1c (#B51C1C). The colour is a red tone with 73% saturation and 41% lightness. Explore its conversions, colour palettes, gradients, accessibility data, and CSS code below.
Color Conversions
Accessibility Contrast
WCAG contrast ratios for #B51C1C against common backgrounds.
Complementary Colors
#B51C1C paired with its color wheel opposite for maximum contrast.
Analogous Colors
Hues at 330, 0, and 30 degrees for harmonious combinations.
Triadic Palette
Three colors at 0, 120, and 240 degrees.
Color Palettes Using #B51C1C
Five shades at lightness levels 15% through 85% while keeping hue at 0 and saturation at 73%. Use the darkest shade for text and the lightest for backgrounds to build a cohesive single-hue design system.
Adjacent hues from 0 to 45 degrees create a warm, unified palette. This analogous scheme works for marketing materials, seasonal campaigns, and any design that needs visual warmth without clashing colors.
Combines the base color at hue 0 with its complement at 180 and two adjacent cool tones. This split-complementary approach provides strong visual contrast while remaining more balanced than a pure complementary scheme.
Five evenly spaced hues at 40% saturation and 80% lightness. Pastels are gentle on the eyes and work well for dashboards, onboarding screens, category tags, and any interface where multiple distinct colors are needed without visual aggression.
Shades & Tints of #B51C1C
Lightness variations at hue 0 and 73% saturation.
CSS Gradients with #B51C1C
Design Use Cases for #B51C1C
Vibrant Brand Color
#B51C1C has a strong 73% saturation that makes it ideal for brand identity elements. Use it for logos, primary call-to-action buttons, hero section accents, and marketing materials where visual impact matters. This saturation level is eye-catching without being harsh.
Primary Interface Color
At 41% lightness, #B51C1C is in the mid-range, making it ideal for interactive elements like buttons, links, and selected states. This lightness level ensures good contrast against both light and dark adjacent elements in most layouts.
Urgency & Energy Signaling
#B51C1C falls in the red spectrum (hue 0). Red triggers urgency and excitement, making it effective for sale badges, countdown timers, error messages, and "limited time" labels. In data visualization, use it to flag negative values or critical thresholds.
Gradient Pairing
Create a gradient from #B51C1C (hue 0) to its complement at hue 180. For a subtler effect, try pairing with an analogous color at hue 30. Use CSS: background: linear-gradient(135deg, #b51c1c, #1cb5b5);
CSS Code for #B51C1C
Similar Colors
Colors visually similar to #B51C1C based on RGB, lightness, and hue variations.
Use This Color in Design Tools
Apply #B51C1C across image editing and color design tools.
About Color #B51C1C (#B51C1C)
#B51C1C is a red color (colour) with RGB channel values of 181 red, 28 green, and 28 blue. The red channel is dominant by a ratio of 6.5:1 over the weakest channel. In HSL terms, the hue sits at 0 degrees with 73% saturation and 41% lightness, placing it in the warm range of the colour spectrum.
The perceived brightness of #B51C1C is 74/255 using the ITU-R BT.601 luma formula (0.299R + 0.587G + 0.114B). This appears dark to the human eye, so pair it with light text for adequate readability. For print production, the CMYK equivalent is 0% cyan, 85% magenta, 85% yellow, and 29% key (black).
The WCAG contrast ratio of #B51C1C against white is 6.67:1 and against black is 3.15:1. This meets the AA requirement (4.5:1) for normal text on white. For AAA compliance, consider darkening to at least 29% lightness.
The complementary colour #1CB5B5 creates maximum visual tension when paired with #B51C1C. For more harmonious color combinations, use the analogous colours #B51C69 and #B5691C, which sit 30 degrees on either side of the hue wheel. To build a complete design system, start with the monochromatic scale above for consistent shade variations, then add one complementary or triadic accent for interactive elements.
How to Explore Color #B51C1C
- Enter your color value in HEX format.
- The tool converts it to RGB, HSL, CMYK format in real time.
- Copy the converted value to your clipboard.
What is HEX to RGB, HSL, CMYK color conversion
Converting from HEX to RGB, HSL, CMYK translates a color value between two different color models. Different color models are used in web design (HEX, RGB), print (CMYK), and color theory (HSL, HSV).
Related Tools & Colors
Frequently Asked Questions
- What color / colour is #B51C1C?
- #B51C1C is Color #B51C1C, a red color (colour) with RGB(181, 28, 28), HSL(0, 73%, 41%), and CMYK(0%, 85%, 85%, 29%). Its perceived brightness is 74/255.
- Is #B51C1C accessible for text?
- Against white, #B51C1C has a contrast ratio of 6.67:1 (passes AA for normal text). Against black, it has 3.15:1 (fails AA). Use the contrast checker tool for custom background pairings.
- What colours pair well with #B51C1C?
- The complementary colour is #1CB5B5 (hue 180). For subtle color combinations, use analogous colours #B51C69 and #B5691C. The triadic palette adds #1CB51C and #1C1CB5 for vibrant variety.
- How do I use #B51C1C in CSS?
- Use any format: color: #b51c1c; or rgb(181, 28, 28); or hsl(0, 73%, 41%). For CSS custom properties: --color-primary: 0 73% 41%; then use it as hsl(var(--color-primary)).
- Is this color / colour explorer free?
- Yes, completely free with no signup required. All colour calculations run in your browser. You can explore any valid hex color code, not just the pre-generated palette.