A vehicle that sits unsold for 45 to 60 days will typically have its entire front-end gross profit consumed by floorplan interest and price markdowns, according to dealership financial trend analysis from Bradyware. That is not a rounding-error rule of thumb. It is a breakeven point you can calculate for any unit if you know its cost, your floorplan rate, and how your pricing tool discounts aging stock.
Most stores track days supply as an inventory metric: a health indicator for the buying team, something that shows up in a monthly report next to turn rate and absorption. Treating it that way misses what is actually happening on the balance sheet. Every day a unit sits past its curtailment clock is a day of accruing interest expense stacked on top of a shrinking price ceiling.
Key insight
Days supply is not an inventory metric wearing a finance costume. It is a margin metric, and it has a breakeven point per unit, not a vague sense that "older is worse."
Why days supply is really a P&L line, not a lot metric
Two things happen simultaneously to a unit that ages past 30 days, and both work against gross.
First, the cost side climbs. Floorplan interest accrues daily on the amount financed, and most lenders require a curtailment paydown at fixed intervals, commonly day 31, day 61, and day 91, whether or not the unit has sold. Miss a curtailment payment and the lender can pull cash unexpectedly, which turns an inventory problem into a cash-flow problem overnight. We cover the mechanics of that schedule in Curtailment at Day 31, 61, and 91: What Changes at Each Stage.
Second, the revenue side falls. Any dealership running an aging-based pricing tool marks units down on a schedule, typically starting around day 21 to 30, because a car that has been listed longer with no offers is, by definition, priced above the market clearing point for that unit. Those two curves (rising cost, falling price ceiling) cross somewhere. Bradyware’s 45 to 60 day figure is where that crossing point lands for a typical unit under typical floorplan terms.
The reframe matters because it changes what you monitor. An inventory-management view asks “is this car getting old?” A margin view asks “on what day does this specific unit stop making me money, and what do I do before that day arrives?” The second question has a number attached. The first one doesn’t.
The math: calculating your own breakeven day
You do not need Bradyware’s number to apply this. You need three inputs you already have: unit cost, your floorplan rate, and your markdown schedule. Here is the shape of the calculation, worked through with illustrative figures so you can drop in your own.
Daily floorplan interest = (amount financed × annual rate) / 365.
Say your store floors a $19,000 unit at a 9% annual rate. That’s roughly $4.68 a day in interest, or about $140 over 30 days. On its own, that number rarely looks alarming, which is exactly why days supply gets under-weighted as a margin risk. Interest alone rarely kills a deal in the first month.
Markdown erosion is the bigger lever, and the one most dealers don’t line up against interest in the same spreadsheet. If your pricing tool cuts an aging unit by, say, $300 to $500 at each markdown interval starting around day 21, and it runs two or three of those cycles by day 60, you’ve given up $600 to $1,500 in list price before the car sells, on top of accrued interest and any reconditioning drift from sitting on the lot.
Breakeven days = front-end gross target ÷ (daily interest + daily markdown-equivalent cost).
Run those illustrative numbers against a modest $1,600 front-end gross target and the combined daily burn (interest plus amortized markdown exposure) clears that target somewhere in the 45 to 60 day window, which is exactly the range Bradyware’s analysis points to. The specific day moves with your rate, your cost basis, and how steep your markdown curve is, which is the point: it’s calculable per unit, per store, not a fleet-wide guess.
The operational implication is that your aging report needs a fourth column next to age, cost, and list price: estimated days to breakeven for this unit at its current markdown pace. A unit at day 35 with an aggressive markdown schedule might already be past its breakeven point even though it doesn’t look “old” yet by a 60-day threshold set on a dashboard somewhere.
What’s actually stacking on top of interest
Floorplan interest is the visible, line-itemed cost. It is rarely the whole story. Four things compound alongside it on a unit that’s aging out:
- Curtailment principal, due at fixed intervals regardless of sale status, which some stores fund out of working capital rather than floorplan draws, adding an opportunity cost that doesn’t show up as “interest” anywhere.
- Reconditioning drift, where a unit sitting longer picks up additional detail, minor repair, or re-inspection costs the longer it’s on the lot and being shown.
- Opportunity cost of capital, the fact that money tied up in an aging unit isn’t buying the next unit that would turn faster.
- Markdown-driven gross compression, covered above, which is usually the largest single factor and the one least visible on a standard aging report.
None of these show up individually as alarming. Stacked, across a lot running any meaningful volume, they are the difference between a healthy front-end average and a store quietly bleeding gross on whichever slice of inventory is aging past that breakeven point every month. If you want the fuller mechanics of what triggers a curtailment notice in the first place and how the schedule interacts with your floorplan line, the complete guide to floorplan curtailment walks through it end to end, and What Is Curtailment? A Plain Explanation for Ops Leaders is the shorter version if you need to bring a GM up to speed fast.
Why days supply has been drifting up industry-wide
This isn’t purely a store-level discipline problem. Bradyware’s analysis also flags a broader 2026 pattern: gross profit per unit is normalizing back down toward pre-pandemic levels while overhead (labor, utilities, software) stays at record highs, which means the margin cushion that used to absorb a slow-turning unit is thinner than it was two years ago. Fewer stores can afford to let a car ride past day 60 without noticing, because there’s less gross elsewhere in the deal to offset the loss.
Trade-in and remarketing flows have also slowed at points in the cycle, which pulls used-inventory turn timelines with it even when a store’s own buying discipline hasn’t changed. The result is that days supply creeping from the high 30s toward 50 or 60 isn’t always a sign that your buyers bought wrong. Sometimes it’s the market. Either way, the breakeven math above still applies: it tells you which units are past the point of no return regardless of why they’re aging.
How to act on this before day 60, not after
The fix isn’t a better dashboard alert at day 60. By then the breakeven point has usually already passed. It’s building the aging report so it surfaces the estimated breakeven day per unit starting around day 15 to 20, when there’s still room to reprice aggressively, wholesale the unit, or move it to a different store in the group before the curtailment clock and the markdown curve both start working against you at once.
For stores where curtailment notices and aging exceptions already eat into someone’s morning every day, the pattern is usually the same one we see across title, funding, and audit workflows: the rules for when to flag a unit are known, they’re just not applied consistently the moment a threshold is crossed, because nobody’s job is to check every unit every day. That’s the same operational gap covered in How to Avoid Curtailment Fees Without Slashing Prices, and it’s the kind of daily, rules-based check that Deskflow is built to run without adding headcount to watch a spreadsheet.
FAQ
At what point does aged inventory stop being profitable?
Industry commentary points to roughly 45 to 60 days as the window where accumulated floorplan interest expense, combined with the price markdowns most aging-pricing tools apply, catches up to and erases the front-end gross on a typical unit. The exact day depends on your unit cost, floorplan rate, and markdown schedule, which is why it’s worth calculating per store rather than relying on a single industry figure.
Why did days supply rise industry-wide going into 2026?
Analysts point to a combination of thinner margin cushions (gross per unit normalizing down while overhead stays elevated) and slower trade-in and remarketing flows, both of which pull used-vehicle turn timelines longer even without a change in buying discipline. It’s a macro pressure on top of, not a replacement for, store-level inventory management.
Is floorplan interest alone enough to erase gross on a unit?
Rarely by itself. Interest on a typical unit usually runs a few dollars a day, which adds up over months more than weeks. What closes the gap faster is the combination of interest, curtailment principal due at fixed intervals, and the price markdowns most stores apply automatically as a unit ages, which is why breakeven analysis needs to account for all three, not interest in isolation.