Understanding Stock Screeners: How to Filter 12,000 Stocks to Your Best 10
A stock screener is only as good as the criteria you put into it. Learn how to combine fundamental and technical filters, avoid the most common mistakes, and use screener results alongside breadth signals for better timing.
A stock screener is a tool that filters a large universe of stocks down to a smaller set meeting your specific criteria. The starting universe is ~12,000 US stocks — far too many to analyse individually. A well-configured screener reduces that to 20–100 candidates for further research.
The screener is the first step, not the last. Screener results require chart analysis, sector context, and timing judgement before any trading decision. Screeners surface candidates; they don't make decisions.
Technical vs. fundamental filters
Screeners typically offer two categories of filters:
Technical filters — Price, volume, moving average relationships, RS scores, percentage moves, ATR, 52-week high proximity, percentage above/below key MAs. These are backward-looking price-based signals that work independently of a company's business quality.
Fundamental filters — EPS growth, revenue growth, profit margins, P/E ratio, debt levels. These assess the business quality driving (or expected to drive) the stock's performance.
The most powerful screeners combine both. O'Neil's CAN SLIM methodology is a famous example: the fundamental criteria (accelerating EPS/sales growth, institutional sponsorship) identify high-quality businesses; the technical criteria (Stage 2 uptrend, near 52-week highs, base formation) identify the right time to buy them.
Average volume > 500k/day — ensures meaningful liquidity
50-day SMA above 200-day SMA — confirms Stage 2 uptrend
Price within 5–15% of 52-week high — captures stocks near potential breakout zones, not extended or in base early stages
RS Score above 70 — stocks outperforming most of the market
Volume surge — recent volume above 1.5× 50-day average (institutions are active)
The most common screener mistakes
Too many filters: Each added filter reduces the result set. With 15 strict filters, you might get 3 results — too few to find quality setups on most days. Start with 4–6 core filters.
Using screeners in the wrong market: A screener that works brilliantly in a bull market will produce garbage results in a bear market or sideways chop. Check the Breadth tab regime before running a screener — in Risk-Off conditions, most technical screener results should be ignored for longs.
Ignoring the chart: A stock can pass every screener filter and still have a terrible chart — an extended, late-stage run with no base, or a pattern that's too deep and volatile. Always look at the chart after a screener result.
Combining screeners with breadth signals
The highest-quality screener results come when technical criteria align with a supportive market regime:
Run screeners during Risk-On breadth conditions — the results are more actionable and have higher follow-through rates.
Focus screener results on the top 3–4 sectors by RS score from the Leaders tab — you want the best stocks in the best sectors.
Cross-reference the Gainers/Losers tab — stocks appearing on both the screener results AND the Gainers list are showing strong leadership characteristics from multiple angles.
The WideRadar Charting tab includes a built-in screen builder covering all the key technical criteria above, pre-filtered for quality and Leadership Score.