Guide
The insight most multi-listing sellers miss: you do not need to configure every item individually. Set one account-level repricing default — target lowest competitor, respect a minimum margin — then override the floor only for the listings that truly need it. That two-layer approach lets Undercut watch hundreds of SKUs simultaneously, undercutting rivals on every one of them, while a hard floor on each item ensures you never sell below cost no matter how aggressive the market gets.
Undercut separates setup into two layers so you spend minutes, not hours per SKU. At the account level you choose a single default undercut rule — for example, beat the lowest competitor by $0.01 — plus your repricing cadence by plan. Every listing follows that rule automatically. The second layer is each listing's own hard floor: any listing can carry a floor Undercut will never cross, regardless of the undercut rule. If the market crashes and competitors list below your cost, Undercut holds your price at that listing's floor rather than following them down.
A floor that is too low destroys margin; one that is too high costs you sales. The correct floor covers every cost you will actually incur. Work through this example for a small electronics accessory: item cost $8.00, shipping supplies and postage $4.00, eBay final value fee 13.25% of the total sale price, and a minimum acceptable margin of 15%. Because the fee and margin are both percentages of the sale price, solve for it: floor = (cost + shipping) / (1 − fee% − margin%) = $12.00 / (1 − 0.1325 − 0.15) = $12.00 / 0.7175 ≈ $16.73. Round up to $16.80 and that is the floor you enter in Undercut. The platform will never reprice below that number, so every sale at or above it is profitable by construction.
For sellers with hundreds or thousands of listings, the practical question is where to spend the most care when setting per-listing floors. In most catalogs, roughly 70–80% of SKUs share similar margin profiles, so you can reuse the same floor math across them quickly. Reserve your closest attention for three situations: items with unusually high acquisition cost (liquidation lots, rare collectibles), items in categories with atypical eBay fee structures (media items carry a lower fee, which shifts the floor down), and items you purchased at varying costs across restocking runs. For everything else, the standard formula gives you the floor to enter. This is what makes managing repricing across many eBay listings tractable rather than exhausting.
Speed and strategy interact differently across catalog sizes. At small volumes — the Free plan covers 25 listings — hourly repricing is usually fast enough because your competitors are not moving that quickly. As your catalog grows past a few hundred listings, a faster cycle matters more because you are competing in more sub-niches simultaneously. Undercut's Pro plan reprices every 15 minutes and adds AI aggressiveness tuning, which you set per listing to control how sharply that listing moves toward its floor as it undercuts the lowest competitor. The Scale plan runs on the same 15-minute cycle across up to 10,000 listings, with priority support, and is designed for liquidators and wholesale resellers managing large catalogs. In all cases the floor constraint is enforced at every reprice cycle, regardless of how aggressive the AI setting is.
The most frequent error is setting a floor based on purchase price alone and forgetting the eBay fee. A seller who paid $20 for an item and sets a $22 floor believes they are making $2 per sale. After a 13.25% final value fee on $22, they net $22 − $2.915 = $19.09 — a loss of $0.91 on every transaction. The second mistake is a single global floor across all categories, which ignores that eBay charges different fee rates by category. The third is never updating floors after supplier price changes. Undercut does not know your new landed cost — that update must come from you by editing the listing's Floor Price in the dashboard. Build a calendar reminder to audit floors quarterly, or whenever a major supplier invoice arrives.
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Start freeIf I change my account-level default rule, does it override floors I already set on individual listings?
No. Changing your default undercut amount updates how far below the lowest competitor Undercut prices — but it never overrides a per-listing floor you have set. The floor on each listing is a separate, protected value. If you want to raise or lower floors, you edit each listing's Floor Price in the dashboard.
What happens when every competitor's price drops below my floor?
Undercut holds your listing at the floor price rather than following competitors down. Your listing will not be the lowest price in those moments, but you will not sell at a loss. Once competitors raise their prices above your floor again, Undercut resumes normal repricing and undercuts them automatically.
Can I set floors as a percentage of cost rather than a fixed dollar amount?
Currently Undercut stores floors as a fixed dollar amount per listing. The recommended workflow is to calculate your margin-inclusive floor (cost + shipping + fees + minimum margin %) as a dollar figure and enter that value. The free eBay profit calculator on the Undercut site walks through this calculation for any category's fee structure.
How do I manage repricing for listings I add frequently without reconfiguring from scratch each time?
New listings automatically inherit your current default undercut amount, so the repricing behavior carries over. You set the Floor Price on each new listing in the dashboard, calculated from that item's own cost. For frequent restockers, keeping your floor formula in a spreadsheet makes it quick to look up the right number and enter it before you go live.
Does Undercut reprice listings that are already at the buy box price, or only ones being undercut?
Undercut reprices any listing where a lower-priced competitor exists, including listings that are currently winning but could be challenged. If your listing is already the lowest and no competitor undercuts you, Undercut holds the current price rather than lowering unnecessarily — protecting margin while you hold position.
Related: How to Avoid Selling Below Cost on eBay · What Is a Price Floor? · Multi-Listing Repricing Strategy · Repricing Without Losing Margin · High-Volume Repricing on eBay · Free eBay Profit Calculator