Finviz

Finviz (Financial Visualizations) is the most powerful free stock screener on the internet. The platform lets you filter the entire US stock market across dozens of fundamental, technical, and descriptive criteria — market cap, P/E ratio, dividend yield, 52-week performance, RSI, moving averages, float short, and many more — all with a visual heat map that makes patterns instantly visible.

The heat map is Finviz's signature feature. It displays the entire S&P 500 (or other index) as colored blocks sized by market cap, with green for gainers and red for losers. One glance tells you what sectors are moving and which stocks are driving the action. For quick market reconnaissance, nothing beats it.

Finviz Elite ($39.50/month) adds real-time data, premarket quotes, advanced charting, backtesting, and email alerts. But the free version is remarkably comprehensive. For fundamental screening, technical scanning, and market visualization, Finviz is a daily-use tool for millions of investors.