A drive-in sells out at a number of cars, and that number comes from the field, not the screen. Convert acres to square feet, take off the share used by the screen tower, entrance lanes, snack bar and projection booth, and divide by the footprint each car needs including its aisle. ROUNDDOWN, because a half a space is a car that does not get in.
A 4.5-acre lot is 196,020 sq ft; 65% is parking, and at 250 sq ft per car that is 509.65 — a 509-car sellout.
The example
Three screens. The big field runs tighter rows; the small twin gives each car a wider space for tailgates and lawn chairs.
| A | B | C | D | E | |
|---|---|---|---|---|---|
| 1 | Site | Acres | Usable % | Sq ft per car | Cars |
| 2 | Starlite main | 4.5 | 65% | 250 | 509 |
| 3 | Big field | 8.0 | 60% | 250 | 836 |
| 4 | Twin screen 2 | 2.75 | 70% | 275 | 304 |
The formula
One formula per screen:
How it works
Four factors, one of which you should measure rather than guess:
B2*43560converts acres to square feet. 4.5 acres is 196,020 sq ft.*C2keeps only the share that cars actually park on. Ramps, lanes, the screen setback and the concession pad are typically 30–40% of a lot./D2divides by the footprint per car: the space itself plus its share of the driving aisle. 250 sq ft is roughly a 10 × 18 ft space with an aisle share.ROUNDDOWN(...,0)drops the fraction. 509.65 is 509 cars; the 0.65 of a space is where the trash barrel goes.
The honest way to set C2 is to count the cars on your fullest night and back-solve: Cars*D2/(B2*43560). Then the formula predicts what a re-striped lot or a wider space would do.
Try it: interactive demo
Enter lot acres, the percent that is parking, and the square feet each car takes including its aisle share.
Variations
Sellout revenue
Cars times per-car value from the revenue recipe. This is the ceiling for any single show.
Cars per row
If you know the row length, cars per row is the length over the space width, rounded down.
Pitfalls & errors
Square feet per car must include the aisle. A 9 × 18 ft space is 162 sq ft, but the driving lane behind it adds 80–100 sq ft per car. Using 162 will overstate capacity by half.
Trucks backed in with tailgates and SUVs with hatches open take more depth. Many drive-ins reserve the back rows for them at 300+ sq ft; run those rows as a separate line.
Usable percent is a share of the parking field, not of the deeded parcel. If your 4.5 acres includes a wooded buffer, take that off the acreage first.
Practice workbook
Frequently asked questions
What is a typical usable percentage?
Should I count the front rows the same as the back?
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