By ColorblindSimulator Team7/25/2025 • 18 min read

Best Color Blind Simulators & Accessibility Testing Tools (2025 Guide)

Color blindness affects over 350 million people worldwide, including 1 in 12 men and 1 in 200 women. For designers and developers, using the best color blind simulators and color blindness simulation tools is essential for accessibility testing and inclusive UI design. This guide compares the top tools, explains their benefits and limitations, and shows how to integrate them into your workflow for better, more accessible products.

Color Blindness: Key Facts & Impact

• Globally, about 4.5% of the population is color blind (Colour Blind Awareness).
• Red-green color blindness is the most common, affecting up to 8% of men and 0.5% of women of Northern European descent.
• Color blindness can make it difficult to distinguish UI elements, read charts, or complete forms if color is the only cue.
• Accessibility standards like WCAG require that color is not the only means of conveying information.

“Color blind simulation is a must-have for any accessibility testing workflow.”
— W3C Web Accessibility Initiative

What Are Color Blind Simulators?

Color blind simulators are tools that let you preview images, websites, or UIs as they appear to people with different types of color vision deficiency (CVD), such as Protanopia, Deuteranopia, Tritanopia, and Achromatopsia. They help you:

• Spot accessibility issues early in the design process
• Comply with legal and ethical accessibility standards
• Build empathy for users with color vision deficiencies

Best Color Blind Simulators & Tools (2025)

Here’s a detailed look at the top color blindness simulation tools for designers, developers, and accessibility testers:

1. ColorblindSimulator.app Recommended
   • Features: Simulate Protanopia, Deuteranopia, Tritanopia, and Achromatopsia on images, live websites, or via webcam. Includes a Website Checker, Image Simulator, Webcam Simulator, and Palette Checker.
   • Benefits: Free, no sign-up, mobile-friendly, supports all major CVD types, downloadable results, and privacy-friendly (no uploads stored).
   • Limitations: Website screenshots may not work for password-protected or highly dynamic sites.
   • Use Case: Designers previewing UI mockups, developers testing live sites, accessibility audits.
   
2. Coblis (Color Blindness Simulator)
   • Features: Upload images and preview them under various color blindness filters.
   • Benefits: Simple, web-based, supports multiple CVD types.
   • Limitations: No live website or webcam simulation, no batch processing.
   • Use Case: Quick image checks for designers and educators.
   • Try Coblis
3. Sim Daltonism (Mac App)
   • Features: Real-time color blindness simulation for any part of your Mac screen.
   • Benefits: Free, works with any app or website, instant feedback.
   • Limitations: Mac-only, not available for Windows or Linux.
   • Use Case: Designers working on Mac who want to check any UI instantly.
   • Download Sim Daltonism
4. Chrome DevTools (Vision Deficiency Emulation)
   • Features: Built-in simulation for Protanopia, Deuteranopia, and Tritanopia in Chrome’s DevTools.
   • Benefits: No installation needed, works on any website, great for developers.
   • Limitations: Only simulates in-browser content, not images or native apps.
   • Use Case: Frontend developers testing live web apps.
   • How to use Chrome DevTools for color blindness simulation
5. Adobe Photoshop & Illustrator Proof Setup
   • Features: “Proof Setup” modes for Protanopia and Deuteranopia.
   • Benefits: Professional-grade, integrated into design workflow.
   • Limitations: Paid software, limited to static images.
   • Use Case: Graphic designers finalizing assets for accessibility.
   • Adobe Photoshop Proof Setup
6. Color Oracle
   • Features: Free desktop app for Mac, Windows, and Linux. Simulates color blindness on your entire screen.
   • Benefits: Cross-platform, easy to use, works with any software.
   • Limitations: No image upload or web-based simulation.
   • Use Case: Developers and designers needing a quick, system-wide check.
   • Download Color Oracle

Feature Comparison Table

Practical Use Cases & Workflow Tips

• UI/UX Designers: Preview mockups and prototypes for accessibility before handoff.
• Developers: Test live websites and apps using browser tools or simulators.
• Accessibility Auditors: Document issues and provide screenshots for reports.
• Educators: Demonstrate color blindness to students and teams.
• Teams: Share simulation results to build empathy and drive inclusive design decisions.

Workflow Tip: Integrate simulation into your design review process. Test early and often, and combine simulators with WCAG and contrast checkers for best results.

Expert Opinions & Accessibility Standards

“Simulating color blindness is a critical step in accessible design. It helps teams catch issues that automated checkers can’t.”
— Smashing Magazine, Accessible Data Visualization

• WCAG 2.1 (1.4.1): “Color is not used as the only visual means of conveying information, indicating an action, prompting a response, or distinguishing a visual element.”
• WebAIM: “Testing with color blindness simulators is recommended for all visual content.” (WebAIM: Visual Disabilities)

Frequently Asked Questions

• What is the best color blind simulator for web designers?
  ColorblindSimulator.app is highly recommended for its web-based, multi-mode simulation and accessibility features.
• Are there free color blindness simulation tools?
  Yes! ColorblindSimulator.app, Coblis, Sim Daltonism, Chrome DevTools, and Color Oracle all offer free simulation options.
• How do I test my website for color blindness?
  Use Color Blind Website Checker or Chrome DevTools’ vision deficiency emulation.
• Do simulators guarantee accessibility compliance?
  No, but they are a vital part of a complete accessibility testing workflow. Always combine with contrast checks and manual review.

Conclusion: Make Your UI Truly Inclusive

The best color blind simulators empower you to design and build products that work for everyone. By integrating simulation tools into your workflow, you’ll catch issues early, comply with accessibility standards, and create a more inclusive digital world. Start today—small changes can make a big difference.