Opposite Color Calculator

About Opposite Color Calculator

This tool calculates the RGB-inverted (opposite) color by subtracting each RGB channel from 255. The result produces the photographic negative of the input color. This differs from complementary colors on the color wheel, which are determined by rotating hue 180°.

The calculator shows both the input and output colors as visual swatches, along with hex and RGB values for easy copying and use in design projects.

RGB Inversion Formula

RGB Inversion:
  R' = 255 - R
  G' = 255 - G
  B' = 255 - B

Example: #3498db
  Original:  R=52,  G=152, B=219
  Inverted:  R=203, G=103, B=36
  Result: #CB6724 (burnt orange)

Hex to RGB Conversion:
  #3498db → 34, 98, db (hex pairs)
  0x34 = 52, 0x98 = 152, 0xdb = 219

JavaScript Implementation

// Parse hex color to RGB
function parseHex(hex) {
  if (hex.startsWith("#")) hex = hex.slice(1);
  // Handle 3-digit shorthand: #FFF → #FFFFFF
  if (hex.length === 3) {
    hex = hex[0]+hex[0] + hex[1]+hex[1] + hex[2]+hex[2];
  }
  if (!/^[0-9a-fA-F]{6}$/.test(hex)) return null;
  return {
    r: parseInt(hex.slice(0, 2), 16),
    g: parseInt(hex.slice(2, 4), 16),
    b: parseInt(hex.slice(4, 6), 16)
  };
}

// RGB to hex
function toHex(n) {
  const s = Math.round(Math.max(0, Math.min(255, n))).toString(16);
  return s.length === 1 ? "0" + s : s;
}

// Calculate inverted color
function invertColor(rgb) {
  return {
    r: 255 - rgb.r,
    g: 255 - rgb.g,
    b: 255 - rgb.b
  };
}

// Full calculation
function calculateOpposite(hexInput) {
  const rgb = parseHex(hexInput);
  if (!rgb) return null;
  const inverted = invertColor(rgb);
  const hexOut = "#" + toHex(inverted.r) + toHex(inverted.g) + toHex(inverted.b);
  return { original: rgb, inverted: inverted, hex: hexOut };
}

Inversion vs Complementary Colors

Color Wheel Reference

Traditional Color Wheel (RYB model):

                    Red (0°)
                   /        \
                  /          \
           Purple             Orange
              |                  |
              |                  |
           Blue -------------- Yellow
              \                  /
               \                /
             Green           (Yellow-Green)

Complementary Pairs (180° apart):
  Red ←→ Green
  Blue ←→ Orange
  Yellow ←→ Purple

Digital Color Wheel (RGB model):
  Red ←→ Cyan
  Green ←→ Magenta
  Blue ←→ Yellow

Common Color Inversions

WCAG Contrast Ratio Guide

Color Contrast Examples

High Contrast (Good for text):
  #000000 on #FFFFFF = 21:1 ✓ (Black on White)
  #FFFFFF on #000000 = 21:1 ✓ (White on Black)
  #333333 on #FFFFFF = 12.6:1 ✓ (Dark Gray on White)
  #FFFF00 on #000000 = 19.6:1 ✓ (Yellow on Black)

Medium Contrast (Use for large text only):
  #777777 on #FFFFFF = 4.5:1 ✓ (Medium Gray on White)
  #0066CC on #FFFFFF = 4.5:1 ✓ (Blue on White)
  #FF6600 on #000000 = 4.8:1 ✓ (Orange on Black)

Low Contrast (Avoid for text):
  #CCCCCC on #FFFFFF = 1.6:1 ✗ (Light Gray on White)
  #6699CC on #336699 = 2.1:1 ✗ (Similar blues)
  #FF9999 on #FF6666 = 1.4:1 ✗ (Similar reds)

Applications of Color Inversion

• Dark mode: Invert light backgrounds for dark themes
• Accessibility: Create high-contrast alternatives for visually impaired users
• Negative effects: Create photographic negative effects in image editing
• Selection highlighting: Use inverted colors for selection states
• Print styles: Invert colors for print-friendly dark backgrounds
• Error states: Use complementary colors for error highlighting