Floor plan interest costs unit cost times APR divided by 365 per day. A $12,000 car at 8% costs $2.63 a day. Hold it 45 days and that is about $118 before a dollar of overhead. That is the minimum your car costs for every day it sits.
- Daily interest
- $2.63
- Daily total (interest + overhead)
- $2.63
- Total holding cost over 45 days
- $118.36
- Break-even price drop
- $118.36 (1.0% of cost)
Calculator assumptions: a $12,000 unit at 8% APR held 45 days with $0 daily overhead; replace with your own numbers. Estimates only. Also available as the standalone holding cost calculator.
If you buy at Copart, IAAI or Manheim and finance the unit, this is the number to keep next to your max bid.
LocalIQ™ market snapshot
What top flip candidates are asking right now
| Model | Listings | Median asking price |
|---|---|---|
| GMC Sierra 1500 | 632 | $29,972 |
| Honda Civic | 5,396 | $15,000 |
| Honda Accord | 4,176 | $15,999 |
| Ford F-150 | 3,134 | $24,000 |
| Toyota Corolla | 3,040 | $14,500 |
| Nissan Sentra | 3,004 | $9,880 |
| Toyota Camry | 2,510 | $17,082 |
| Hyundai Elantra | 2,396 | $9,499 |
LocalIQ™ asking-price median · 24,288 listings · updated every 6 hours. National, last 8 model years; asking price is your resale ceiling.
The formula
Daily interest = unit cost x APR / 365
Total holding cost = (daily interest + daily overhead) x days held
Some lenders count a 360-day year or add curtailment rules, so check the day-count basis in your own agreement. The structure does not change.
Run it with your numbers in the holding cost calculator. It works in your browser and sends nothing to a server.
Daily interest by unit cost and APR
| Unit cost | 6% APR | 8% APR | 10% APR |
|---|---|---|---|
| $5,000 | $0.82 | $1.10 | $1.37 |
| $10,000 | $1.64 | $2.19 | $2.74 |
| $20,000 | $3.29 | $4.38 | $5.48 |
| $35,000 | $5.75 | $7.67 | $9.59 |
The 6, 8 and 10% rates are round numbers for illustration, not quotes from a lender. Use your own APR.
What 30, 60 and 90 days do to one car
Take the $12,000 car at 8%, which is $2.63 a day:
| Days held | Interest |
|---|---|
| 30 | $78.90 |
| 60 | $157.81 |
| 90 | $236.71 |
Add overhead and the line steepens. At $5 a day for insurance and lot cost, the 60-day total is about $458.
The break-even price drop
The calculator also returns a break-even price drop: the holding cost for the days you would wait. If your choice is between selling now at a lower price and waiting 30 more days at the full price, any cut smaller than the 30-day holding cost leaves you ahead, all else equal.
For the $12,000 car with $5 a day of overhead, 30 more days costs about $229 (30 x $7.63). A $150 cut to sell this week costs less than waiting. It ignores depreciation, which only makes waiting costlier.
The fuller formula: Cox Automotive
Interest is only the financing slice. Cox Automotive publishes a per-unit formula that covers the whole operation:
Holding cost per unit per day = (total monthly expenses − monthly selling expenses) ÷ units in stock ÷ selling days
Its worked example uses $91,048 of monthly expense, 85 units in stock and 24 selling days, which gives $44.63 per unit per day. At a 60-day turn, Cox puts the cost of holding one unsold unit at about $2,677 against a $3,000 profit example. Those figures describe the example dealership, not yours. The takeaway is the method: divide what you spend to keep a lot open across the cars on it. Source: Cox Automotive, "Three Floor Plan Finance Formulas Every Dealer Should Know" (July 2017).
Cox also writes that once a unit moves past the 60-day point, you should start thinking about what might become frozen capital, or an inadequate return on investment. Treat 60 days as an alarm, not a target.
Put real days-to-sell in the formula
The calculator is only as good as the days you feed it. In CarFlipIQ's Q3 2026 data, the average timed sale took 14.6 days and 70.0% closed within 15 days (n=32,691). Some models are well above that: see days to sell by model, where the Honda Civic averaged 18.9 days (n=2,627) and the Chevrolet Tahoe 8.7 (n=135).
A practical routine:
- Look up days to sell for the model in your state's market report.
- Enter that number in the calculator to get the holding cost you should expect.
- Subtract it from your resale margin before you set a max bid on the max bid calculator.
- Set a day-15 checkpoint and a day-45 decision point.
On the buy side, remember what comes before the lot: Copart fees, IAAI fees, transport and tax. The auction cost guide walks the full stack.
Know the days before you bid.
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