What is a good gap % to look for?

For small-cap momentum, most traders start filtering at 5% gap up (or down) with above-average pre-market volume. Below 5% is usually noise; 10%+ with a catalyst and high relative volume is a genuine gap-and-go candidate.

Is there a free gap scanner?

Yes. Momentum Scan runs a free daily gap scan every morning that ranks pre-market gappers by relative volume, with a price ceiling filter designed for small trading accounts.

Guide

Gap Scanner: How to Find Pre-Market Gappers Every Morning (2026)

Q: What is a gap scanner?

A gap scanner is a tool that lists stocks trading meaningfully higher or lower than yesterday's closing price before the market opens. Day traders use it to build a pre-market watchlist of stocks with fresh catalysts and unusual volume.

A gap scanner is the single most useful tool in a day trader's morning routine. It shows you which stocks are trading meaningfully higher or lower than yesterday's close — before the market opens — so you can build a pre-market watchlist of names with fresh catalysts instead of guessing which ticker to trade at 9:30.

What is a gap scanner?

"Gap" is the difference between yesterday's regular-session close and the current pre-market price. A gap scanner ranks the market by that percentage change, usually with a minimum volume filter so you don't get flooded with illiquid tickers. A stock gapping up 15% on 20× relative volume with a fresh earnings beat is a very different setup from one gapping 2% on nothing.

Why gaps matter for momentum traders

A large gap = something changed overnight: earnings, FDA news, an offering, an analyst upgrade, a viral squeeze.
Gaps with real volume attract other momentum traders — that liquidity is what makes intraday continuation possible.
Focused watchlists beat "watching everything" — a good gap scanner narrows the whole market down to 5–15 tickers worth your attention.

The filters that actually matter

Every gap scanner will let you set some combination of these filters. Start narrow — you can always loosen them if the list is too short.

Gap %: minimum 5% for small-caps, 3% for large-caps.
Relative volume (RVOL): at least 2×; 5× and above is where the real setups live.
Price ceiling: if you trade a small account, cap price so results are shares you can actually size into ($10, $20, $50).
Catalyst: news, earnings, a filing — a gap without a "why" is a lower-probability setup.

A simple morning gap-scanning routine

Open your gap scanner around 8:00–8:30am EST. This is when pre-market volume has enough print to be meaningful.
Filter for gap ≥ 5% and RVOL ≥ 3×. Cap price at whatever your account can size into.
For each name, check the catalyst: is there news, earnings, or an SEC filing? "Nothing" is a red flag.
Trim to 3–5 tickers with the cleanest pre-market charts (a real move, not a single-print spike).
Set alerts on your top 2 — pre-market high, gap fill level, and your invalidation.

Free gap scanner: Momentum Scan

Momentum Scan — Pre-Market Gappers

Free — no card

Momentum Scan runs an automatic gap scan every trading morning. It ranks pre-market gappers by relative volume, filters by a max share price so results fit a small account, and shows the reason each ticker moved.

See today's gappers

Gap-and-go vs. gap-fill

The two most common gap plays are "gap-and-go" (buy strength continuing above the pre-market high) and "gap-fill" (fade the move back toward yesterday's close). The scanner tells you which stocks are candidates — your job is to pick the setup that matches the tape on that specific ticker.

Run today's scan

The pre-market gapper list refreshes every morning before the open. Free, no card, no download.

Open the gap scanner

Not investment advice. Gap trading involves substantial risk — position size for a fixed dollar loss and set your stop before you enter.