Race Fuel Calculator

Where the extra lap comes from

A 60-minute race is almost never 60 minutes of driving. In the standard timed-race format the clock expires while the leader is mid-lap; the leader completes that lap, takes the white flag and runs one more, and everyone still on track finishes with them. That is why this calculator adds one lap on top of the ceiling division in timed mode and prints it as its own line in the budget - iRacing's own Auto Fuel feature budgets exactly one extra lap for the same reason. On a timed track day or test session the same lap exists: it is the one you finish after the checkered flag flies, and your in-lap belongs in the formation and out-lap count. Fixed-lap races get no lap from the clock, which is one reason margin still matters there: a late safety car or an extended finish can stretch the race past the number on the entry list.

Fuel per lap is the number that lies

Every figure on this page is a multiple of one input, and it is the input people measure worst. A single flying lap in clean air on low fuel is your best case, not your average: traffic, dirty air, a heavier tank at the start and pace swings all push real burn up. Measure it the boring way - fill the tank, run a full stint, refill and divide fuel by laps - and use that number. The verdict above states exactly how much burn error your margin absorbs; if that percentage looks smaller than a normal race's chaos, add a lap.

Sim rig or paddock, same arithmetic

iRacing and ACC drivers run this math before every endurance event, and it is the same sum a track-day driver does in the paddock: laps per tank is the tank divided by the burn, rounded down - never up. Some iRacing cars meter fuel in kilograms rather than liters; pick the kg unit and enter burn and tank exactly as the sim shows them, and every lap count and stop stays right. If the day involves gearing decisions as well as fuel, the gear ratio calculator covers the sprocket math, and the top speed calculator tells you what the straight is worth.