Discount Detective

Calculate real discount percentages after applying caps and hidden charges.

A privacy-first calculator to expose "Marketing Math" on any shopping site. Don't let "Up to 80% Off" banners trick you. Discount Detective is a manual utility that helps you verify if a deal is actually worth it—on any website, anywhere. Why use this? Sales are confusing. A "50% Off" coupon with a small "Max Cap" is often just marketing hype. Instead of doing mental math, simply open Discount Detective in the side panel, enter the price and the cap, and see the Real Effective Discount instantly. Features: ✅ Works Everywhere: Use it on any ecommerce store or a food ordering website (Amazon, Flipkart, Nike, Zomato etc.). ✅ Input-Based Accuracy: You control the data, so the math is always right. ✅ Side Panel Mode: Multitask easily while you browse product pages. ✅ 100% Private: No data leaves your device. ✅ Open Source: Transparent code you can trust. Support: Built by a solo developer to help shoppers save money. If you have feature requests, let us know on our GitHub page!