How to Use Complementary Colors in Web Design | Tips to Make Elements Stand Out Without Looking Too Flashy
Complementary colors sit opposite one another on the color wheel. They can help draw attention to important parts of a website, but using both colors across equally large areas may make the page feel overly intense—or even make text and buttons harder to identify. The goal is not to maximize the amount of complementary color. It is to choose a dominant hue, assign a clear role to the second hue, and check contrast against the actual surrounding backgrounds.
Start with hues 180 degrees apart, then adjust lightness and coverage
A color wheel arranges hues, or families of color such as purple and yellow-green, in a circle. In HSL (a way to describe color by hue, saturation, and lightness), moving 180 degrees around the wheel produces a complementary hue. For example, purple #5B2A7E at 275 degrees and yellow-green #4D7E2A at 95 degrees form a complementary pair. Both examples start at 50% HSL saturation and 33% HSL lightness, with minor rounding when converted to HEX, the hexadecimal notation used for web colors.
Yet purple #5B2A7E placed directly beside yellow-green #4D7E2A has a contrast ratio of only about 2.09:1. A contrast ratio measures the difference in relative luminance between adjacent colors. Hues that face opposite directions on the wheel do not automatically provide the contrast needed for meaningful text or the only visual boundary identifying an interactive control.
Instead, use purple as the dominant introductory color. Make the yellow-green lighter or darker depending on whether it will appear on purple or on a nearly white surface. Keep the reading area and cards mostly neutral so the two strong hues do not compete across the entire page.
Example palette for a livestream concert sign-up page
Imagine a site showing performers, event times, viewing-ticket options, and early registration for an online music event. Complementary purple and yellow-green can remain recognizable while each part of the layout has a distinct function.
- Event introduction: Use deep purple #5B2A7E as the background, with the event name and date in white #FFFFFF. Text-to-background contrast is about 10.11:1.
- “Meet the performers” button on purple: Use a lighter yellow-green #C2E2AC surface with charcoal #302C35 lettering. Text contrast is approximately 9.61:1, while the button surface differs from the surrounding purple #5B2A7E by about 7.11:1.
- Performer information and ticket prices: Use an off-white #FAF9F5 reading background with charcoal #302C35 text. Their contrast ratio is about 12.97:1. Keep long paragraphs and prices away from large saturated backgrounds.
- Performer and ticket-option cards: Set charcoal #302C35 text on white #FFFFFF cards, giving about 13.66:1 contrast. White cards #FFFFFF against the surrounding off-white #FAF9F5 differ by only about 1.05:1, so use a gray #7A7A82 outline. That border has approximately 4.26:1 contrast with the white #FFFFFF card.
- Viewing instructions and notices: Put charcoal #302C35 text on a pale lavender-gray #F1F0F4 panel. The text contrast is about 12.04:1. A gray #7A7A82 border against this panel has approximately 3.75:1 contrast.
- Small “Early registration” label: Use the original complementary yellow-green #4D7E2A with white #FFFFFF lettering. The contrast ratio is about 4.85:1. Also state the registration dates in words so the meaning does not depend on color alone.
- “Book a viewing ticket” button: On the light content background, use a darker adjusted yellow-green #3F6921 with white #FFFFFF lettering. Text contrast is approximately 6.45:1, while the button differs from the surrounding off-white #FAF9F5 by about 6.13:1.
- Text links to event details: Use deep purple #5B2A7E on off-white #FAF9F5 for approximately 9.60:1 contrast. Underline the links so they remain distinguishable from ordinary body text.
The yellow-green family serves as a light button against the purple introduction and a dark booking button against the pale content area. The complementary hue relationship remains, but the actual saturation and lightness are adjusted to match the background where each element appears.
Reduce visual intensity without sacrificing readability
First, check whether large purple and yellow-green sections alternate throughout the page. A purple introduction, neutral reading area, and a few yellow-green actions or labels often provide a clearer hierarchy than two equally dominant colors. Pale lavender-gray #F1F0F4 also differs from off-white #FAF9F5 by only about 1.08:1, so separate those sections with headings and spacing rather than relying on surface color alone.
Under WCAG 2.2 (Web Content Accessibility Guidelines) Level AA, normal-size text generally needs a contrast ratio of at least 4.5:1 against its background and large text at least 3:1. Essential non-text indicators needed to identify controls or states, including certain form-field outlines, generally need at least 3:1 against adjacent colors. When moving a button, check both its lettering and its visual boundary against the new background. Make registration and availability states clear through words as well as color.
On mobile devices, review small performer names, ticket-card outlines, and the placement of the booking button. HueRoll offers complementary-color suggestions and contrast comparisons between a selected color and white or black. It cannot directly compare arbitrary pairs of custom colors or automatically determine WCAG AA or AAA conformance. The custom-pair contrast ratios in this example were calculated separately.