Inspection Hours Remaining Calculator
Hours remaining to your next inspection and the estimated calendar date it lands, from current times and daily utilisation.
Hours-based inspections land on a date you can estimate: remaining hours ÷ daily utilisation. Planning shop time off that estimate is what keeps revenue aircraft out of surprise downtime.
Remember the 100-hour rule's overflight trap: exceeding by up to 10 h to reach the shop is allowed, but the overage deducts from the NEXT interval (91.409(b)).
With your numbers: Since the last inspection at 3,782.5 h you've flown to 3,847.2 h; on a 100 h interval that leaves 35.3 h remaining — about 14.71 days at 2.4 h/day.
⚠️ Not for operational decisions. This is a record-keeping and planning aid only — not certified avionics, not a source of regulatory truth. Always verify against official sources (FAA) and your operator's approved documents before flying.
Free inspection-hours calculator: current times in, hours remaining and an estimated due date out — the arithmetic behind every fleet's scheduling board, done correctly in one screen.
About Inspection Hours Remaining Calculator
Every hours-based inspection — 100-hour, phase, progressive event, oil change — eventually becomes a calendar problem: WHEN does it land? The conversion is simple division (remaining hours ÷ average daily utilisation) but doing it continuously, per aircraft, is exactly the chore that gets skipped until an inspection lands mid-season. This calculator does the conversion live: enter current and last-inspection times, the interval, and your realistic daily utilisation; read hours remaining and the estimated date. Schools and charter operators run this math weekly because an inspection forecast is a revenue forecast — every day of unplanned downtime is cancelled bookings.
How to use Inspection Hours Remaining Calculator
- 1Enter current time, time at last inspection, and the interval.
- 2Set your honest average daily utilisation.
- 3Read hours remaining and the estimated due date; book the shop accordingly.
Why use Inspection Hours Remaining Calculator?
- ✓Hours remaining AND the estimated calendar date — the number scheduling needs
- ✓Works for any hours-based interval: 100-hour, phase, oil, progressive events
- ✓Utilisation-aware: the same 40 hours is 6 weeks for one owner, 6 days for a school
- ✓Notes the 91.409(b) overflight deduction trap
- ✓Instant, free, browser-only
Frequently asked questions
Can I fly past a 100-hour inspection to reach the shop?+
Yes, by up to 10 hours — but only to reach a place where the inspection can be done, and the excess deducts from the next interval: fly to 104 and the next 100-hour is due at 200, not 204 (91.409(b)). The allowance exists for positioning, not planning; an operation that routinely uses it is an operation whose scheduling math (this calculator's job) isn't being run.
What utilisation figure gives an honest due-date estimate?+
Your trailing 30–60 day average, not the aspirational one: pull total hours flown over the last month or two and divide by days. Seasonal operations should use the season's figure — a trainer flying 90 hours a month in June makes a 'yearly average' forecast uselessly optimistic. Re-run the estimate as utilisation shifts; it's one division, and the date moves more than people expect.
Does this work for progressive and phase inspections?+
Yes — any event defined by an hour interval fits: enter the phase interval and the time at the last phase event. For progressive programs the discipline matters doubly, because a missed phase deadline can invalidate the whole program and revert the aircraft to needing a full annual. Forecast each phase's landing date and the program stays the availability advantage it was designed to be.
Where is this data stored?+
Everything you enter is saved in your browser's local storage on your own device — nothing is uploaded to any server. Your records stay completely private, work offline, and load instantly. Use the CSV export regularly to keep an off-device backup copy.
Can I export these records for an audit?+
Yes — one click exports your complete inspection forecast as a CSV file that opens in Excel, Google Sheets or Numbers. The export preserves every column exactly as entered, so you can print it, attach it to paperwork, or hand it to an inspector, buyer or insurance underwriter as a supporting summary alongside your official records.
Related Aviation tools
FAA PPL Pilot Logbook
Free digital FAA pilot logbook for PPL holders — log flights, auto-total hours and watch 90-day recency, privately in your browser.
● LiveFAA CPL Pilot Logbook
Free digital FAA pilot logbook for CPL holders — log flights, auto-total hours and watch 90-day recency, privately in your browser.
● LiveFAA ATPL Pilot Logbook
Free digital FAA pilot logbook for ATPL holders — log flights, auto-total hours and watch 90-day recency, privately in your browser.
● Live