Color Contrast Checker
Check foreground/background contrast against WCAG standards with AA/AAA rating.
Daily Free Usage Exceeded
Used 10 / 10 times today
Log in to get more daily usage, or upgrade to PRO for unlimited access to all tools.
Resets automatically at midnight (00:00), free usage continues the next day.
📖 Instructions
How to Use
❓ FAQ
What is the contrast standard?
WCAG requires 4.5:1 for body text (AA) and 3:1 for large text.
Does it support hexadecimal colors?
Yes, both HEX and RGB color input are supported.
🔗 Related Tools
📝 Related Articles
Beware! Your IP Address Is Exposing Your Home Address
An IP address is not just a meaningless string of numbers; it's like your home's network house number. With lookup tools, it can directly locate your city, street, or even residential complex. Everyday activities like browsing, commenting, or connecting to Wi-Fi can leak your IP, which, if exploited, can lead to harassment or even fraud. This article reminds everyone not to casually fill in personal information, to be cautious with public networks, to change default device passwords, and suggests checking your own IP to see what's exposed, raising awareness to protect privacy.
tool-tutorialsThe days of not understanding JSON formatting and being blamed by colleagues are over
This article explains in plain language the practical value of JSON formatting tools. Starting from daily scenarios like colleagues shifting blame, taking over messy projects, and integration testing comparisons, it shows that formatting tools can help you clarify data, quickly report errors, and precisely compare differences, saving time and effort while avoiding blame. It emphasizes that knowing how to use tools is true intelligence, teaching you to solve the most annoying problems with minimal cost, and saying goodbye to the hard days of searching through messy JSON.
tool-tutorialsChanged a JS compression config, online errors dropped by 80%
Frequent JS errors online? Don't rush to blame the logic; 80% of the time it's the compression config causing trouble. This article uses real cases to show you how the compressor's default "smart" settings can ruin old projects, from mis-deleting conditional branches to messing up variable names. Step-by-step, I'll teach you to turn off a few key optimization options, cutting error rates by 80% while only increasing code size by 15%, in exchange for stable operation—totally worth it.
tool-tutorialsWhat Hackers Do with Your IP: Today I'll Teach You to See Through It in Three Seconds
IP address lookup tools can help you quickly identify the real location behind the other end of the network, preventing fraud, detecting account theft risks, and seeing through netizen disguises. Don't be intimidated by complex terms—the operation is simple, just paste and see results, but also know its limitations: dynamic IPs and VPNs can affect accuracy, so learn to use it wisely to protect yourself.