How is floorplan cost calculated?

Floorplan interest is the amount financed on a unit multiplied by the annual floorplan rate, divided over the year. Per unit per day it is amount financed × (APR ÷ 365); across the lot, multiply by your unit count. The longer a unit sits, the more days of that daily cost it accrues before it sells.

Why does days-in-stock matter to floorplan cost?

Every day a unit stays in inventory adds another day of floorplan interest and, usually, more depreciation. Aging is where floorplan cost compounds — ten extra days across a full lot can quietly erase a meaningful share of a month's gross.

Is floor plan the same as floorplan?

Yes. "Floor plan" and "floorplan" are the same thing: the revolving credit line a dealer uses to finance inventory, repaid unit by unit as each car sells. This works as a dealer floor plan calculator under either spelling. Enter the amount financed per unit, your floor plan rate, unit count and average days in stock.

What is your floorplan really costing you?

Floorplan interest (most lenders and dealers write it “floor plan”) is the cost you feel but never see on a line. Move the sliders to your store and watch the carrying cost add up — per unit, per month, and per ten days a car ages on your lot.

Units in stock120Avg. amount financed / unit$28,000Floorplan APR8.5%Avg. days in stock62 days

Monthly floorplan interest$23,800$285,600 a year in carrying cost

$6.52per unit, per day

$7,825every 10 days your lot ages

$48,513riding on your lot at 62 days

An estimate for planning only. Real floorplan carries curtailments, tiered rates and per-lender terms GhostDrive tracks unit by unit.

The math is simple; the habit is the hard part. A unit's floorplan cost is the amount financed times your annual rate, spread over the days it sits — a few dollars a day that most stores only add up at month-end, if at all. Multiply it across the lot and stretch it over the aging you already carry, and floorplan quietly becomes one of the largest line items nobody watches daily. It is worth knowing how many of those days are real before you cost them — phantom units age on the report forever.

This is an estimate for planning. Real floorplan carries curtailments, tiered rates and per-lender terms, and it moves every time you stock or sell a unit. That's exactly why it belongs on a live screen rather than a spreadsheet — the Floorplan module tracks it unit by unit, and the daily KPI dashboard keeps aging in front of you before it compounds.

What the default store is paying.

The sliders open on a plausible mid-size used-car operation: 120 units on the lot, $28,000 financed per unit, 8.5% floorplan APR, 62 days average time in stock. Here is what that store is spending to hold its inventory, worked through.

Start with one car. $28,000 at 8.5% is about $2,380 a year in simple interest — the same basis the calculator above uses, before curtailments and tiered rates — which works out to $6.52 a day, small enough that nobody mentions it. That unit sitting the full 62-day average has eaten about $404 in interest before it sells. Let it slip another 30 days and it takes $196 more, straight off the front gross you were negotiating to protect.

Now the lot. 120 units at $28,000 is $3.36M financed, so the store pays roughly $23,800 a month and $285,600 a year in floorplan interest. At the 62-day average, about $48,500 of interest is riding on the cars currently in stock. Every ten days the whole lot ages costs roughly $7,800.

That last number is the one worth pinning up. Ten days of average aging costs this store roughly $7,800, and nearly $48,500 of interest is riding on the cars in stock at any given moment — which is why a days-supply number that counts cars you no longer have is not a reporting nitpick. It hides a five-figure cost behind a metric that looks fine. Move the sliders to your own numbers above; the shape of the answer rarely changes, only the size.

Questions dealers ask.

How is floorplan cost calculated?: Floorplan interest is the amount financed on a unit multiplied by the annual floorplan rate, divided over the year. Per unit per day it is amount financed × (APR ÷ 365); across the lot, multiply by your unit count. The longer a unit sits, the more days of that daily cost it accrues before it sells.
Why does days-in-stock matter to floorplan cost?: Every day a unit stays in inventory adds another day of floorplan interest and, usually, more depreciation. Aging is where floorplan cost compounds — ten extra days across a full lot can quietly erase a meaningful share of a month's gross.
Is floor plan the same as floorplan?: Yes. "Floor plan" and "floorplan" are the same thing: the revolving credit line a dealer uses to finance inventory, repaid unit by unit as each car sells. This works as a dealer floor plan calculator under either spelling. Enter the amount financed per unit, your floor plan rate, unit count and average days in stock.

Stop guessing what the lot costs to hold.

GhostDrive tracks every unit's financing cost to the day — interest accruing, curtailments coming due, and aging that eats the gross before the car sells. The carrying cost you feel but never see, finally on a line.