Why do people keep mentioning 4.5:1 and 7:1?

4.5:1 is the common WCAG AA threshold for normal text, while 7:1 is the stricter AAA target. These numbers describe how much brightness difference exists between foreground and background. In general, a higher ratio is easier to read.

Why are large text and normal text judged differently?

Larger or bolder text is easier to recognise, so WCAG allows a lower contrast threshold for large text. That said, important content still benefits from stronger contrast whenever possible.

Is meeting AA always enough?

AA is a practical baseline for most products, but it is not the ceiling. If your interface is dense, used in difficult viewing conditions, or serves more low-vision users, aiming for AAA is safer.

Can I use the suggested colors as-is?

Usually yes as a starting point, but you should still review them in the real interface. Check brand fit, visual hierarchy, and states such as hover, disabled, and dark mode before treating them as final.

Does a good ratio guarantee good readability?

Not completely. Contrast ratio is a strong baseline, but font weight, size, spacing, textured backgrounds, and actual screen conditions also affect readability. Use the ratio together with visual review.

WCAG Contrast Checker

Enter your text and background colors to instantly check contrast ratio and WCAG 2.x accessibility compliance.

Supports HEX input with live preview, AA/AAA compliance check, and color improvement suggestions.

Report

Color inputs

Text Color

Background Color

Quick Presets

Preview

Normal text — a sample paragraph at regular size (16px)

Large text — a heading sample (24px)

Bold large text — a subheading sample (18.67px bold)

Contrast Ratio

— :1

—

1:1 3:1 4.5:1 7:1 21:1

WCAG 2.x Compliance

Level	Normal Text	Large Text
WCAG AA Normal 4.5:1 / Large 3:1	—	—
WCAG AAA Normal 7:1 / Large 4.5:1	—	—

Normal text: < 18pt or < 14pt bold (approx. < 24px or < 18.67px bold)

Large text: ≥ 18pt or ≥ 14pt bold (approx. ≥ 24px or ≥ 18.67px bold)

Color Improvement Suggestions

Design Tips

Insufficient contrast makes text hard to read for users with low vision and on screens in bright light. Aim for at least 4.5:1 for body text.

Large text (≥ 18pt or bold ≥ 14pt) has a lower threshold of 3:1 because larger characters are inherently easier to read.

WCAG AAA is the strictest standard. Aim for 7:1 or higher on important body text and detailed descriptions for maximum accessibility.

Set text and background

Pick colors with the swatches or type HEX values. Use Swap on the toolbar to exchange text and background, or try a quick preset.

Read the preview and ratio

The preview panel shows sample text, the contrast ratio, a pass/fail style label, and where you sit on the 1:1–21:1 track.

Check WCAG and apply fixes

The table lists AA/AAA results for normal and large text. The suggestions panel offers one-click colors that move you toward AA or AAA.

When should I use this tool?

Whenever you are designing web, slides, dashboards, or app screens and want a fast read on text vs. background clarity—or when brand colors are fixed but you still need a sanity check against accessibility goals.

Why do people mention 4.5:1 and 7:1 so often?

4.5:1 is the familiar WCAG AA target for normal body text; 7:1 is the stricter AAA goal. Both describe how much luminance difference exists between foreground and background—higher is usually easier to read.

Why is large text judged differently?

Larger or bolder type is easier to recognise at a glance, so WCAG allows a lower contrast threshold for large text. Important content still benefits from stronger contrast whenever you can justify it.

Is passing AA always enough?

AA is a solid baseline for most products, but it is not a ceiling. Dense UIs, harsh viewing conditions, or audiences with more low-vision users are good reasons to aim for AAA.

Can I ship the suggested colors as-is?

Treat them as a fast correction path. Always review in the real interface for brand fit, hierarchy, and states such as hover, disabled, and dark mode before calling them final.

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WCAG Contrast Checker

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