Are NanoTools completely free to use?

Yes, all basic tools on NanoTools are completely free to use with no registration required. We offer premium features for power users.

Is my data secure when using NanoTools?

Your files are processed securely and are automatically deleted after processing. We do not store your files or data on our servers.

Do I need to install any software to use NanoTools?

No installation required. All tools work directly in your browser on any device - computer, tablet, or smartphone.

What file formats are supported?

We support a wide range of formats including PDF, JPG, PNG, WebP, GIF, JSON, XML, CSV, and many more depending on the tool.

Color Contrast Checker - WCAG Compliance

Check color contrast online for free. Test WCAG accessibility compliance. A11y validator.

HTML Color Contrast Checker

Check WCAG accessibility contrast ratios

Colors

Foreground (Text)

Background

Font Size: 16px (Large Text)

The quick brown fox jumps over the lazy dog

Contrast Ratio

21.00:1

WCAG AA Pass

Minimum 3:1 for large text

WCAG AAA Pass

Minimum 4.5:1 for large text

WCAG Guidelines:

AA (Minimum): 4.5:1 for normal text, 3:1 for large text
AAA (Enhanced): 7:1 for normal text, 4.5:1 for large text
Large text: 18px+ regular or 14px+ bold
Higher ratios = better readability for users with visual impairments

What This Tool Does

Calculates WCAG contrast ratios
Tests AA and AAA compliance levels
Checks normal and large text standards
Live preview of color combinations
Shows exact contrast ratio (e.g., 7:1)

How to Use

1
Choose colors
Select foreground (text) and background colors
2
Set font size
Specify text size (affects WCAG requirements)
3
Check compliance
See if colors pass AA or AAA standards
4
Adjust as needed
Modify colors until compliance is achieved

How it works

1

Choose colors

Select foreground (text) and background colors

2

Set font size

Specify text size (affects WCAG requirements)

3

Check compliance

See if colors pass AA or AAA standards

4

Adjust as needed

Modify colors until compliance is achieved

Use Cases

Ensuring website accessibility compliance
Designing accessible color palettes
Validating brand colors for readability
Meeting legal accessibility requirements
Improving UX for visually impaired users

Frequently Asked Questions

What is WCAG?

Web Content Accessibility Guidelines - international standards for web accessibility.

What is the difference between AA and AAA?

AA is minimum (4.5:1 normal, 3:1 large). AAA is enhanced (7:1 normal, 4.5:1 large).

What counts as large text?

Text 18px+ or 14px+ bold is considered large text.

Is AA compliance required by law?

In many jurisdictions yes - ADA and Section 508 require WCAG AA compliance.