Advanced Color Contrast Calculator
Enter foreground and background colors. The calculator checks contrast ratio, relative luminance, normal text status, large text status, and non-text contrast.
Saved Result Table
Each calculation is added here. Export this table as CSV or PDF.
| # | Foreground | Background | Ratio | Normal Text | Large Text | Non-text | Best Quick Text | Note |
|---|---|---|---|---|---|---|---|---|
| No saved results yet. | ||||||||
Example Data Table
Use these common pairs as reference checks before testing your own palette.
| Foreground | Background | Ratio | Result |
|---|---|---|---|
| #111111 | #FFFFFF | 18.88:1 | AAA |
| #777777 | #FFFFFF | 4.48:1 | Near AA |
| #0D6EFD | #FFFFFF | 4.50:1 | AA |
| #FFFFFF | #198754 | 4.53:1 | AA |
Formula Used
The calculator uses the standard relative luminance and contrast ratio method. Each color channel is first converted from sRGB to linear RGB.
For each red, green, or blue channel:
c = value / 255.
If c <= 0.03928, then linear = c / 12.92.
Otherwise, linear = ((c + 0.055) / 1.055) ^ 2.4.
Relative luminance is:
L = 0.2126R + 0.7152G + 0.0722B.
Contrast ratio is:
(L1 + 0.05) / (L2 + 0.05),
where L1 is the lighter luminance.
- Normal text AA target: 4.5:1 or higher.
- Normal text AAA target: 7:1 or higher.
- Large text AA target: 3:1 or higher.
- Large text AAA target: 4.5:1 or higher.
- Non-text contrast target: 3:1 or higher.
How to Use This Calculator
- Choose a foreground color using the picker or hex field.
- Choose a background color using the picker or hex field.
- Enter the planned font size and font weight.
- Add preview text and a project note if needed.
- Click the calculate button to display results above the form.
- Review pass levels, luminance, preview, and suggested text color.
- Download the saved table as CSV or PDF for records.
Why Color Contrast Matters
Good contrast makes text easier to read. It also supports people with low vision, color weakness, glare issues, or small screens. A strong color pair keeps content clear when users move between devices, rooms, and lighting conditions. Poor contrast can hide buttons, labels, warnings, and links. That can reduce trust and raise bounce rates.
Design Value
This calculator helps you test color choices before publishing a page. You can enter foreground and background colors, then review the contrast ratio, luminance values, and accessibility pass levels. The preview box shows the pair in use, so you can judge both numbers and visual comfort. The black and white recommendations also help you choose a safer quick option.
Accessibility Planning
Contrast is not only a design detail. It is part of inclusive planning. Normal text usually needs a stronger ratio than large text. Icons, borders, and controls also need enough visual separation. When contrast is weak, users may need to zoom, strain, or abandon the task. Better color planning reduces that friction.
Practical Workflow
Start with your brand colors. Test headings, body text, buttons, cards, alerts, and form fields. Save each result to the table. Export the CSV for spreadsheets, or create a PDF for review notes. Share the report with writers, designers, clients, and developers. This keeps decisions documented and repeatable.
Best Practices
Do not rely on color alone. Add labels, icons, patterns, and clear wording. Test hover states and disabled states too. Check colors on mobile screens and under bright light. Avoid placing thin light text over images unless you add an overlay. Use consistent palettes, but allow exceptions when readability needs them. A beautiful interface must still be usable. Contrast testing gives your design a simple quality gate before launch.
Common Mistakes
Many teams test only final screens. Test early instead. Contrast problems become costly after templates, images, and campaigns are approved. Watch gradients, shadows, thin fonts, transparency, and disabled controls. These details can lower readable contrast. Build a small color checklist for every release. Review dark mode separately, because copied colors may fail on different surfaces. Keep evidence inside design files for faster future audits.
FAQs
What is a color contrast ratio?
A contrast ratio measures the brightness difference between foreground and background colors. It ranges from 1:1 to 21:1. Higher values usually mean better readability.
What ratio should normal text pass?
Normal text should usually reach at least 4.5:1 for AA. A ratio of 7:1 or higher is stronger and meets AAA for normal text.
What counts as large text?
Large text is usually 24px or larger. Bold text can count as large around 18.66px or higher. Large text has lower contrast requirements.
Can color contrast improve conversions?
Yes. Clear buttons, labels, and links reduce user effort. Better readability can improve trust, completion rates, and form usability across many page types.
Should I test icons and borders?
Yes. Important icons, input borders, focus outlines, and controls need enough contrast too. A 3:1 ratio is a common target for non-text elements.
Why do some brand colors fail?
Brand colors may look attractive but still lack enough brightness difference. Pair them with darker or lighter supporting colors when text readability matters.
Does font size affect the result?
The ratio stays the same, but pass levels can change. Large or bold text can pass at lower ratios than small body text.
Can I export my checks?
Yes. After calculating, saved checks appear in the result table. You can download them as a CSV file or a PDF report.