Stock Screener Filters Explained: How Day Traders Find the Best Setups

Why Screener Filters Are a Day Trader's Most Important Tool

Day trading is a game of selectivity. On any given trading day, 50–200 stocks will produce significant intraday moves worth trading. The remaining 8,000+ tickers are noise. Without screener filters, you either limit yourself to a small watchlist and miss opportunities, or you drown in data trying to monitor everything.

The right combination of screener filters solves this. Instead of watching everything, you define the exact characteristics of the setups you trade — then let the screener do the work of surfacing them from the entire market.

This guide covers the 8 most important day trading screener filters, what each one measures, how to set meaningful thresholds, and how to combine them into a composite score that ranks candidates by quality.

Filter 1: Relative Volume (RelVol)

What it measures: Today's volume compared to the average volume for this time of day.

Relative volume is the single most important day trading filter. It tells you that something unusual is happening right now — a catalyst exists, participants are paying attention, and the stock is in play. A stock with 5× relative volume has traded five times more shares than it typically would by this point in the session. This almost always means news: earnings, FDA decision, regulatory filing, analyst upgrade, M&A rumor, or unusual options activity.

Threshold guidance:

• 1.5× — Minimum for consideration; the stock is active but the move may lack conviction
• 2×–3× — Good threshold for most setups; elevated participation, likely catalyst
• 4×+ — High priority; significant news catalyst likely driving the move
• 10×+ — Extreme activity; the stock is the day's mover, typically with major catalyst

Common mistake: Treating relative volume at 3:45 PM the same as relative volume at 9:45 AM. Volume naturally spikes into the close. Early-session high relative volume (before noon) is far more significant than late-session relative volume.

Filter 2: ATR Percentage (ATR%)

What it measures: The Average True Range expressed as a percentage of price — essentially, how much the stock moves on an average day.

Day trading requires range. If a stock typically moves 0.5% per day, even a perfect setup only offers a few cents per share of profit. A stock that moves 5% daily has enough range for meaningful entries, stops, and targets.

Calculation: ATR ÷ Current Price × 100. A $20 stock with a $1.20 ATR has an ATR% of 6%.

Threshold guidance:

• Below 2%: Too slow for most day trading strategies; more appropriate for swing trading
• 2%–5%: Solid range for patient, disciplined day traders
• 5%–10%: Strong range; supports multiple trade opportunities per session
• Above 10%: High volatility; position sizing must be reduced proportionally

The position sizing connection: ATR% directly determines your stop-loss distance, which determines position size. A stock with 8% ATR has wider natural swings — your stop must be wider, meaning fewer shares for the same dollar risk. ATR-based stops automatically scale your risk appropriately.

Filter 3: Gap Percentage

What it measures: How much the stock's opening price differs from the previous day's closing price.

Gaps are created by overnight catalysts — earnings releases, FDA decisions, analyst rating changes, M&A announcements. The gap percentage tells you the magnitude of the catalyst's initial market impact.

Threshold guidance by strategy:

• Gap and go (continuation): Filter for 3%–15% gaps up with relative volume 3×+. These stocks gap on catalysts and often continue trending through the morning session.
• Reversal setups: Very large gaps (>20%) often overshoot and pull back. Experienced traders fade the initial extension after the gap-and-go exhausts.
• Gap fill plays: Stocks that gap but immediately show selling pressure may fill the gap — returning to the previous day's close. This is a distinct strategy requiring a different setup.

Pre-market vs. open: Gap percentage is most reliable after the open, when full market participation confirms or rejects the pre-market move. Many pre-market gaps fail to hold when the regular session opens.

Filter 4: Float

What it measures: The number of shares available for public trading.

Float is the supply side of the supply-demand equation. Low float = limited supply = large price swings on moderate buying pressure. High float = abundant supply = smaller price moves on the same order flow.

Categories:

• Micro float: Under 5 million shares — extreme volatility, manipulation risk
• Low float: 5–20 million shares — strong momentum candidates
• Mid float: 20–100 million shares — calmer but still tradeable
• High float: 100M+ shares — large-cap behavior, requires institutional order flow to move

When to use float as a primary filter: Gap-and-go and momentum strategies benefit most from low float (under 20 million). Float rotation analysis — tracking when daily volume equals or exceeds the float — identifies the strongest momentum days.

Filter 5: RSI Range

What it measures: The Relative Strength Index momentum level (0–100 scale).

RSI filters for the momentum regime of your candidates. Rather than using RSI as a standalone signal, use it as a filter to select stocks already in the right momentum state for your strategy.

By strategy:

• Momentum/breakout longs: RSI 55–75 (trending up, not yet overbought)
• Oversold bounce: RSI below 35 at a known support level
• Reversal shorts: RSI above 80 at resistance with bearish candle confirmation

RSI works best when combined with price context — an RSI of 65 at all-time highs suggests continuation; the same RSI at resistance from three months ago suggests caution.

Filter 6: Price Change Percentage (% Change on Day)

What it measures: How much the stock has moved today as a percentage.

Filtering for stocks already in motion focuses your attention on names that have demonstrated directional commitment. Stocks that are up 3–8% by mid-morning have already proven they can sustain a move — they've absorbed the initial supply of profit-takers and are continuing higher.

Guidance:

• 2%–5%: Early mover, move is still developing, potential for continuation
• 5%–15%: Strong mover, confirm with relative volume and catalyst before entering
• 15%–30%: Extended move, higher reversal risk, require pullback entry or skip

Avoid filtering for the biggest movers of the day without context — a 25% gap-up on no volume is far less interesting than a 6% move with 8× relative volume.

Filter 7: Minimum Liquidity (Average Daily Volume + Dollar Volume)

What it measures: How easily you can enter and exit a position without moving the price.

Liquidity is non-negotiable. An illiquid stock may look great on a screener, but when you try to enter a $5,000 position, your own order moves the price. When you try to exit, the bid-ask spread costs you 1–2% of the trade's value.

Minimum thresholds:

• Minimum shares: 300,000+ average daily volume (500,000–1M preferred)
• Minimum dollar volume: $1M+ average daily dollar volume
• Bid-ask spread: Under $0.05 for stocks under $20, under $0.10 for $20–$50 stocks

Trading illiquid stocks is a common beginner mistake. The screener returns them because they have 10× relative volume (easy to achieve on a stock that normally trades 50,000 shares) but the actual dollar volume is tiny. Filter for both relative volume AND minimum absolute volume simultaneously.

Filter 8: Composite Score — Combining All Filters

Pass/fail filtering (a stock either passes or fails each criterion) generates a long list of candidates with no ranking. Composite scoring — weighting multiple factors and producing a single quality score — surfaces the best candidates first.

A simple composite scoring framework:

Each factor is normalized (scaled 0–1) and multiplied by its weight. The resulting score (0–100) ranks every candidate. Trade the top 5–10 by score, not everything that passes filters.

How to Build Your Screener Stack

Step 1: Define your strategy. Different strategies use different filters. Gap-and-go traders prioritize gap % and pre-market volume. Opening range breakout traders focus on ATR% and float. Momentum traders weight relative volume and RSI. Know what you're trading before building your screener.

Step 2: Set your hard gates first. Minimum price, minimum liquidity, and market hours are binary — either a stock is tradeable or it isn't. These eliminate 95% of the universe immediately and should run first.

Step 3: Score, don't filter. For the remaining criteria, use scoring rather than hard thresholds where possible. A stock with 4× relative volume and 6% ATR is a better candidate than one with 2.5× relative volume and 8% ATR — but a binary filter would accept both equally. Scoring differentiates them.

Step 4: Limit candidates. A screener returning 50 candidates is useless. Target 5–15 ranked candidates per session. If your filters return more, tighten the thresholds. More candidates = more decisions = more mistakes.

Step 5: Add AI conviction as the final gate. After the screener ranks candidates technically, an AI conviction layer evaluates each one for setup quality, market context, news sentiment, and historical pattern recognition. This final gate removes technically adequate setups that lack the complete picture needed for high-probability execution.

How Tradewink Implements These Filters

Tradewink's DayTradeScreener applies these principles in a four-stage pipeline. Hard gates eliminate untradeable stocks. Technical scoring combines relative volume (highest weight), ATR%, gap percentage, day range efficiency, and 52-week proximity. User watchlist tickers receive a priority boost — you always see the names you've committed to monitoring first. Finally, the top 25–30 ranked candidates advance to AI conviction scoring, which integrates options flow, news sentiment, market regime, and historical pattern quality before producing a final ranked shortlist for execution.

The entire pipeline runs continuously during market hours, updating as new volume data arrives and new candidates emerge from the morning session.