A working premarket gap scan needs four filters: Gap %, a volume filter that actually calculates before the open, a price range, and float. This guide gives you the exact filter names, the menu path, and starting values for three scan variants, all checked against the official Gap % filter documentation in June 2026.
This is the scan side of the gap-and-go strategy. The strategy page covers entries, stops, and when the setup fails. This page covers finding the candidates in the first place.
Who this is for: traders who own Trade Ideas and want a premarket gapper scan built from scratch, plus anyone deciding whether the software fits their morning routine. If you don’t have it yet, start with our Trade Ideas review before spending anything.
What you need before you start
A paid plan. Per the pricing page (verified June 2026), customizable scans and premarket data are included on both Basic ($89 a month billed annually, $127 month-to-month) and Premium ($178 annually, $254 month-to-month). The free account includes neither, so it can’t run anything on this page.
You do not need Premium to build the custom scans below; Basic carries the full filter library. Premium adds the Channel Bar, which contains the premade gap layouts covered near the end, plus customizable multi-strategy windows. Which tier you need comes down to whether you’d rather build or load: the pricing breakdown runs the annual-versus-monthly math.
One platform note from the official compatibility notice: the desktop software is built for Windows. Mac users run it through virtualization like Parallels or a cloud Windows desktop, or use the browser version.
How the Gap % filter actually works
Worth thirty seconds, because it explains why premarket readings drift. The documented formula is (expected open minus prior close) divided by prior close, times 100. Before 9:30 am ET, “expected open” is simply the most recent print, so the gap reading updates with every premarket trade. It’s a progressively accurate estimate that locks in once the official opening print hits.
Practical consequence: a stock showing a 6% gap at 8:00 am can show 3% by 9:15. That’s not the scanner being wrong. That’s the gap changing. Scan more than once.
Step by step: build the scan
- Open any alert window or Top List window you’re willing to repurpose. All scan settings live in the Configuration Window, and the path is the same for both window types.
- Right-click inside the window and select Configure. The Configuration Window opens with tabs across the top: Strategies, Search, Select Alerts, Window Specific Filters, Exchanges, Symbol List, Columns, and Summary.
- Go to the Search tab and type “gap”. You’ll find Gap % [GUP] and Gap $ [GUD] among the 500+ alerts and filters. Add Gap % to your scan. Use Gap $ only if you trade a narrow price bracket where dollar moves mean the same thing across names; for everything else, percent levels the field between a $4 stock and a $40 one.
- Open the Window Specific Filters tab. This is where every filter gets its values. Each one takes a minimum field, a maximum field, or both, and anything outside your numbers is excluded from results.
- Set the Gap % minimum. Enter 4 in the minimum field to see only stocks gapping up 4% or more. For gap-downs, the convention flips: enter -3 in the maximum field to catch stocks gapping down at least 3%. Per the official documentation, entering 5 in the minimum and -5 in the maximum returns gaps of 5% or more in either direction.
- Add a volume filter that works premarket. This is where most scans silently break, and it gets its own section below. Short version: use Volume Today % [PV] or one of the minute-volume percent filters (Vol5, Vol15, Vol30), not Relative Volume.
- Add Price [Price] and Float [Float]. Both sit in the same tab with the same min/max convention. Float is entered in raw shares: a maximum of 10,000,000 means a float of 10 million or under. The float data comes from Dilution Tracker, per the filter’s documentation.
- Check the Exchanges tab if you want to exclude OTC names, then save. Every filter above is also available as a Top List sort column, so a Top List sorted by Gap % descending with these same filters makes a clean ranked premarket board.
The premarket volume trap
Here’s the part that empties scans: the Relative Volume filter [RV] does not calculate during the premarket. The official filter documentation states it plainly: set a minimum above 1 and you won’t receive any alerts before the open, and your Top Lists will be blank.
This matters because nearly every generic gap-scanning article tells you to demand 2x relative volume on your premarket scan. Follow that advice inside this scanner and you’ll stare at an empty window until 9:30, then conclude the software is broken. It isn’t. RVOL compares current volume to a 30-day average for the same time of day, in 15-minute intervals, and that calculation simply doesn’t run before the bell.
The documented premarket-safe alternatives, straight from the same help page: Volume Today % [PV], plus the minute-volume percent filters Vol1, Vol5, Vol10, Vol15, and Vol30. Volume Today % compares today’s running volume to the average full-day volume over the last 10 days, and it works premarket. A stock reading 10 on this filter before the open has already traded a tenth of a normal full day’s volume. On a low float, that’s the crowd showing up early.
Save Relative Volume for your post-open windows, where it’s genuinely the better tool.
Recommended settings: three scans worth running
These values are starting points with the logic stated, not magic numbers. Tighten them when the market hands you twenty gappers, loosen them on dead mornings. Run the scan around 8:00 am ET to research catalysts and mark levels, then again near 9:15 to catch late movers, and remember premarket data flows early; the premade Premarket channel goes live at 4:00 am ET.
Scan A: low-float momentum gappers. The classic gap-and-go hunting ground. Volatile, thin, and where most of the blowups happen too.
| Filter | Minimum | Maximum | Logic |
|---|---|---|---|
| Gap % [GUP] | 4 | (blank) | Below 4%, gaps fill more often than they run |
| Price [Price] | 2 | 20 | Above $2 avoids the sub-dollar junk; under $20 keeps share size workable |
| Float [Float] | (blank) | 20,000,000 | Small supply is what makes these move |
| Volume Today % [PV] | 10 | (blank) | A tenth of a normal day traded premarket = real participation, not one stray print |
Scan B: mid and large-cap quality gaps. Earnings reactions and real news in liquid names. Smaller percentage moves, far better fills.
| Filter | Minimum | Maximum | Logic |
|---|---|---|---|
| Gap % [GUP] | 2 | (blank) | 2% is a serious move on a $50+ stock |
| Price [Price] | 10 | (blank) | Filters the speculative tier out entirely |
| Avg Daily Volume (10D) [Vol] | 1,000,000 | (blank) | Liquidity you can exit through |
| Volume Today % [PV] | 5 | (blank) | Confirms the gap has buyers behind it |
Scan C: gap-down short watch. Same mechanics, opposite direction. Mind your locates before you lean on this one.
| Filter | Minimum | Maximum | Logic |
|---|---|---|---|
| Gap % [GUP] | (blank) | -3 | Negative maximum = gapping down at least 3% |
| Price [Price] | 5 | (blank) | Sub-$5 gap-downs are where borrows get ugly |
| Avg Daily Volume (10D) [Vol] | 1,000,000 | (blank) | Thin gap-downs trap shorts on the bounce |
The scan finds candidates; it doesn’t grade them. A gapper without a catalyst is a coin flip, so check the news on every name before it earns a watchlist spot. The Earnings Date [EarningD] filter can flag names reporting near today if earnings plays are your lane. Then cut the list to your best three to five, mark premarket high and low, and hand the rest to your premarket routine.
Skip the build: the premade gap channels
Premium subscribers get the Channel Bar, 40+ preconfigured (but customizable) channel layouts, and two are built for exactly this job. The Premarket channel loads gapper Top Lists, a multi-strategy window, and charts starting at 4:00 am ET, showing early movers up and down from the prior close. The Trade The Gap channel takes over after the open, tracking how the morning’s gappers resolve, including both continuation and fade setups.
If you’re on Basic, you’re not missing the capability, just the convenience: the scans above replicate the core of the premarket gapper workflow with your own values. If you’re on Premium, load the channel first and customize from there rather than starting blank.
Troubleshooting
The scan shows nothing premarket. First suspect: a Relative Volume minimum, which blanks premarket results by design (see the trap section above). Second suspect: the free account, which doesn’t include customizable scans or premarket data. Third: filters stacked so tight that nothing qualifies; on a quiet morning, a 4% gap plus a tight float cap plus a volume floor can legitimately return zero, so loosen one constraint at a time.
Gap % numbers keep changing. Normal. Premarket gap is recalculated against the latest print and only locks at the official open. Re-run the scan at 9:15 rather than trusting an 8:00 snapshot.
Too many results. Raise the Gap % minimum, tighten the price band, or sort the Top List by Gap % and work from the top. A watchlist longer than five names usually means the filters are doing too little of the work.
Gap-down scan returns gap-ups. Check which field holds the negative number. Gap-downs need -3 in the maximum field, not the minimum.
Next steps
The scan is the easy part. Most day traders lose money, and a gapper list doesn’t change that; what you do at 9:30 does, so read the day trading statistics before sizing up on anything this scan surfaces.
From here: the gap-and-go strategy page covers trading what the scan finds, our best Trade Ideas scan settings guide extends this into other setups, and if you’re still on the basics, how to use Trade Ideas walks the whole platform. Log every gap trade in the free trading journal template; two weeks of data will tell you whether gappers are your setup or just your habit. Don’t own the software? The full review covers who it’s for and, just as important, who shouldn’t pay for it.
FAQ
What gap percentage should I scan for?
Start at a 4% minimum for momentum names and 2% for liquid mid and large caps, then adjust to how many candidates your market is producing. Smaller gaps statistically fill more often than they continue, which is why a floor exists at all. There’s no universally correct number; there’s the number that gives you three to five tradeable names most mornings.
Why is my premarket gap scan empty?
The usual cause is a Relative Volume minimum above 1, because that filter doesn’t calculate before the open and will return no alerts and blank Top Lists premarket. Swap it for Volume Today % or a minute-volume percent filter and results come back. If that’s not it, confirm you’re on a paid plan and that your remaining filters aren’t impossibly strict for the day.
Do I need the Premium plan for gap scanning?
No. Customizable scans, the full filter set, and premarket data are all included on Basic. Premium adds the Channel Bar with the premade Premarket and Trade The Gap layouts, multi-strategy windows, and the AI signal features, none of which the scans on this page require.
Can I scan for gap-downs too?
Yes. Enter a negative number in the Gap % maximum field: -3 catches everything gapping down 3% or more. Setting a positive minimum and a negative maximum at the same time returns large gaps in both directions in one window.
What time should I run the scan?
Premarket data is available early; the premade Premarket channel activates at 4:00 am ET. Practically, an 8:00 am pass gives you time to check catalysts and mark levels, and a 9:15 pass catches late news. Gap readings keep updating until the opening print, so the later pass is the one to trust.