# Complementary Color Generator

Find the complementary color of any base color with this Complementary Color Generator. Enter a 3 or 6 digit hex code and the tool rotates its hue 180 degrees on the HSL color wheel while keeping saturation and lightness, then returns the base and its complement as hex codes. Ideal for designers and developers who need a high-contrast accent for buttons, highlights, charts and brand graphics.

## Frequently asked questions

### What does the Complementary Color Generator return?

It returns two colors as six digit lowercase hex codes. Color 1 is your base color and Color 2 is its complement, the color directly opposite it on the color wheel.

### How is the complementary color calculated?

The tool converts your hex code to HSL, adds 180 degrees to the hue and keeps saturation and lightness unchanged. The rotated value is converted back to RGB and written as a hex code, so the complement has the same vividness and brightness as the base.

### Which color formats can I enter?

Enter a 3 or 6 digit hex code, with or without the leading #, in upper or lower case, such as #ff5733, FF5733 or #f00. RGB and HSL notation and color names are not accepted here, so convert them to hex first with a color converter.

### Why is Color 1 slightly different from the hex code I entered?

The base color is converted to HSL with whole-number hue, saturation and lightness and then back to hex, so one channel can move by a single step. For example, #ff5733 comes back as #ff5833, and its complement is #33daff.

### What is the complement of pure red?

The complement of #ff0000 is #00ffff, cyan. This tool uses the RGB based HSL wheel used on screens, so red pairs with cyan rather than with green as on a traditional painter's wheel.

### What happens with black, white or gray?

Neutral colors have zero saturation, so rotating the hue changes nothing and both results are the same gray. Pick a base color with some saturation if you need a visible complement.

### How should I use a complementary pair in a design?

Use one color for most of the surface and the complement sparingly for calls to action, highlights or data you want to stand out. Equal amounts of both at full saturation tend to vibrate visually, so tint or shade one of them for large areas.

### Does the tool check text contrast?

No, it only computes the color pair. A complement keeps the lightness of the base, so the two colors can have similar luminance and poor contrast for text; check the pair with a WCAG contrast checker before using one on the other.

### Can I enter several colors at once?

No, each run takes exactly one hex code. Input with several lines or extra text is rejected with an error message, so run the tool once per base color.

### Is the result the same as the Color Palette Generator?

Yes. This tool runs the same calculation as the Complementary option of the Color Palette Generator, so the same base color always gives the same two hex codes in both tools.

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