Aircraft Rental Billing Calculator

Hobbs runs whenever the engine does (often oil-pressure switched) — real elapsed engine time; tach counts revolutions normalised to cruise RPM, so it runs ~10-20% slower across a flight with taxi and pattern work. Schools typically BILL Hobbs (you pay for engine-running time) and MAINTAIN on tach (inspections track engine wear). A renter doing pattern work pays the biggest spread; knowing which clock governs your agreement is line one of invoice literacy.

Wet includes fuel (and oil); dry excludes it — and the details live in the agreement: some wet rates reimburse fuel bought elsewhere at the school's rate, some at your receipt, some not at all (the away-fuel trap on cross-countries). Fuel surcharges, landing fees at towered fields, and after-hours callout fees are the common extras. The fees line in this calculator exists because those items, not the rate, generate most invoice surprise.

Per the school's policy — and asking is the professional move: common models bill from briefing start to debrief end (flight time plus 0.3-0.5 ground), pure flight time only, or scheduled-block regardless. None is wrong; undisclosed is. Schools that print the policy and a worked example invoice (this calculator generates one) take the dispute rate to near zero.

Clearing site data deletes locally stored entries — that's the price of a genuinely private, server-free design. Protect yourself with the one-click CSV download before any cleanup, OS reinstall or device change: re-importing history later beats reconstructing it from memory.

Always — the CSV export is a complete, lossless dump of your billing record, generated locally in one click. Import it into commercial software, archive it with your files, or post-process it in a spreadsheet. No lock-in is deliberate: data you can't take with you isn't really yours.