With thousands of stocks trading each day, finding the right opportunities can feel overwhelming. Stock scanners solve this problem by automatically filtering the market to show only stocks that meet your criteria. This guide explains how day traders use scanners to find high-probability trades.
What is a Stock Scanner?
A stock scanner is a tool that filters through thousands of stocks in real-time based on criteria you define. Instead of manually checking charts, scanners instantly show you stocks that meet your specific requirements like price, volume, percentage change, and technical patterns.
Key difference: Scanners work in real-time, constantly updating as market conditions change. Screeners typically run once and show static results. Day traders need real-time scanners to catch opportunities as they develop.
Why Day Traders Need Scanners
Scanners are essential for day trading because:
- Time savings: Find opportunities in seconds instead of hours
- Consistency: Apply the same criteria every day without human error
- Real-time alerts: Catch moves as they happen, not after
- Focus: Narrow thousands of stocks to a manageable watchlist
Essential Scanner Types for Day Trading
1. Pre-Market Gap Scanner
Gap scanners identify stocks opening significantly higher or lower than yesterday's close. Gaps often lead to strong momentum and trading opportunities.
Pre-Market Gap Scanner Settings
- Gap up: +4% or more from previous close
- Gap down: -4% or more from previous close
- Pre-market volume: 100,000 shares minimum
- Price: $5 to $100 (avoid penny stocks and expensive names)
- Average daily volume: 500,000 minimum
2. Volume Surge Scanner
This scanner finds stocks with unusual volume activity, which often precedes or accompanies significant price moves.
Volume Surge Scanner Settings
- Current volume: 2x or more of normal for this time of day
- Relative volume (RVOL): 2.0 or higher
- Price: $5 to $100
- Percent change: At least +/-2% today
3. Breakout Scanner
Identifies stocks breaking above resistance or below support levels.
Breakout Scanner Settings
- New intraday high (or new intraday low for short setups)
- Breaking above previous day high
- Volume at least 1.5x average
- Price above VWAP (for long breakouts)
4. Momentum Scanner
Finds stocks making strong moves with increasing momentum.
Momentum Scanner Settings
- Percent change: +5% or more in last 30 minutes
- Price above all major moving averages
- RSI between 50 and 70 (not overbought yet)
- Volume increasing
Building Your Day Trading Watchlist
Pre-Market Routine (7:00 - 9:30 AM)
- Run gap scanner: Identify stocks gapping 4% or more
- Check news: Why is each stock gapping? (earnings, upgrades, FDA news)
- Review charts: Look at daily charts for key levels
- Narrow down: Select 3-5 best candidates for your watchlist
- Set alerts: Place alerts at key entry levels
Selection Criteria
From your scanner results, prioritize stocks with:
- Fresh catalyst: News driving the move (not just random activity)
- Clear technical levels: Identifiable support and resistance
- Tradeable range: $10-50 stocks are often best for day trading
- Float consideration: Lower float stocks (under 50 million shares) move more
- Clean chart: Avoid stocks in messy, choppy patterns
Quality over quantity: A focused watchlist of 3-5 stocks is more effective than tracking 20+ names. You cannot watch everything, so choose the best setups.
Real-Time Scanner Usage During Market Hours
First Hour Strategy (9:30 - 10:30 AM)
The first hour has the most volume and volatility. Use these scanners:
- Opening range breakout scanner: Stocks breaking the first 5-15 minute range
- VWAP cross scanner: Stocks crossing above or below VWAP
- High relative volume scanner: Stocks with 3x+ their normal volume
Mid-Day Strategy (10:30 AM - 3:00 PM)
Activity typically slows, so be more selective:
- New high of day scanner: Stocks showing continued strength
- Consolidation breakout scanner: Stocks breaking out of mid-day ranges
- Consider reducing position sizes due to lower liquidity
Power Hour Strategy (3:00 - 4:00 PM)
Volume and volatility often increase:
- Strong close scanner: Stocks near highs of day heading into close
- Weak close scanner: Stocks near lows for potential short setups
Scanner Settings by Trading Style
For Momentum Traders
- Focus on percent change and volume surge
- Look for stocks up 10%+ pre-market
- Prioritize small float, high short interest stocks
- Use news filters to find catalyst-driven moves
For Pattern Traders
- Scan for specific chart patterns (flags, breakouts)
- Filter for stocks near key technical levels
- Use longer timeframes (daily patterns setting up)
- Look for stocks with clear support and resistance
For Reversal Traders
- Scan for oversold or overbought conditions
- Look for stocks at major support or resistance
- Filter for declining volume on moves (exhaustion)
- Use RSI extremes as a filter (under 30 or over 70)
Common Scanner Mistakes to Avoid
- Too many filters: Overly restrictive settings return no results. Start simple and add filters as needed
- Ignoring context: A stock meeting scanner criteria still needs chart analysis and news context
- Chasing scanner alerts: By the time you see an alert, the best entry may be gone. Use scanners to identify candidates, then wait for your setup
- Trading every result: Not every scanner hit is a trade. Apply your trading plan criteria
- Wrong price range: Penny stocks (under $5) can meet criteria but are often untradeable due to spreads and manipulation
Free vs Paid Scanner Options
Free Options
- Finviz: Good basic screener with pre-market data
- TradingView: Decent free scanner with chart integration
- Yahoo Finance: Basic screener for initial research
Paid Options
- Trade Ideas: Professional-grade scanner with AI signals
- TC2000: Powerful scanner with excellent charting
- Benzinga Pro: Scanner with integrated news feed
- Your broker: Many brokers offer built-in scanners
Recommendation: Start with free options to learn what criteria matter to you. Upgrade to paid scanners once you know exactly what you need.
Creating Custom Scanner Alerts
Set up alerts to notify you when stocks meet your criteria:
- Price alerts: Stock hits a specific price level
- Volume alerts: Volume exceeds a threshold
- Percent change alerts: Stock moves a certain percentage
- Technical alerts: Moving average crossovers, RSI levels
Track Every Trade You Take
Pro Trader Dashboard helps you see which stocks and setups from your scanners actually result in profitable trades. Analyze your results by stock, time of day, and strategy.
Summary
Stock scanners are essential tools for day traders to find opportunities in a market with thousands of stocks. Start with basic gap and volume scanners, refine your criteria based on what works, and build a focused watchlist each day. Remember that scanners show you candidates, but your trading plan determines which signals become actual trades.
Ready to learn more? Check out our guide on entry signals for day trading or learn about the best day trading setups.