Fuel is the one cost at a kart track that scales with every single lap, and it is almost always estimated by eye. It does not have to be: a kart burns a known number of gallons per engine-hour, and a race day is a known number of kart-minutes. The only work is the conversion between them.
16 karts running 26 eight-minute sessions is 55.47 engine-hours — 33.28 gallons at 0.6 gallons per hour.
The example
Three days on the same track, with the same fleet burn rate and a $3.75 pump price.
| A | B | C | D | E | F | G | |
|---|---|---|---|---|---|---|---|
| 1 | Day | Karts | Sessions | Min/session | GPH | Gallons | Fuel cost |
| 2 | Weekday | 12 | 14 | 8 | 0.60 | 13.44 | $50.40 |
| 3 | Saturday | 16 | 26 | 8 | 0.60 | 33.28 | $124.80 |
| 4 | Event day | 20 | 30 | 10 | 0.60 | 60.00 | $225.00 |
The formula
The whole calculation is one line, but it is worth reading the /60 as its own step:
How it works
Unit by unit:
B2*C2*D2gives kart-minutes — the total minutes of engine running across the whole fleet. A 16-kart, 26-session day at eight minutes is 3,328 kart-minutes./60converts to engine-hours, because burn rate is quoted per hour. This is the step that gets skipped and turns a $125 fuel day into a $7,500 fuel day on paper.*E2applies the burn rate. Measure it yourself: fill a kart, run it a known number of hours, refill and record. Manufacturer figures are for a load you are not running.ROUND(...,2)keeps the answer at gallons and tenths so the number matches what the pump reads.
Add ten percent for warm-up, idling in the pit lane, and the karts that get run without paying customers in them. That padding is real fuel and it belongs in the order.
Try it: interactive demo
Enter the fleet size, sessions run, session length and your measured burn rate.
Variations
Fuel cost per session
Divide the day's fuel cost by sessions to get the fuel content of one heat — useful when you are pricing an arrive-and-drive session.
Drums to order
Divide gallons by drum size and round up so the delivery arrives before the day does, not during it.
Pitfalls & errors
Burn rate is not constant across a fleet. A four-stroke rental kart and a two-stroke race kart differ by a factor of two or more — give each class its own row rather than averaging them.
Sessions rarely run back to back all day. If you are sizing a fuel order from a schedule rather than from history, use booked sessions and a fill rate, not the theoretical maximum.
Do not mix minutes and hours in one formula without the /60. It is the single most common error in this calculation, and it is off by a factor of sixty, which is large enough that nobody notices it is a unit problem.
Practice workbook
Frequently asked questions
How do I measure gallons per hour properly?
Does session length include the out-lap and the pit lane?
Stop fighting formulas. Learn them in a day.
This recipe is one of hundreds of real-world formulas we teach. Our Excel Formulas & Functions class covers lookups, logic, text, and dynamic arrays hands-on — live in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.
See the Formulas & Functions Class