Busy CFIs can sometimes have to do some careful math to stay under the FAA’s regulation regarding dual-flight instruction given in a 24-hour period regulation (14 CFR § 61.195 (a)).

Under the restrictions of this regulation, a CFI may not provide more than eight hours of flight training in any consecutive 24-hour period. This is a rolling window, not a calendar day. Ground instruction does not count; only flight training time does. Exceed the limit and you are in violation, regardless of how carefully you planned the day.

The practical challenge is real. A late-afternoon dual session yesterday, maybe a night flight, then an early morning lesson today can push you over eight hours without either day looking excessive on its own. Busy instructors juggling multiple students, weather delays, and checkride prep often lose track of the exact total. Manual tracking with a paper log or spreadsheet works until the schedule gets messy. That is where a simple, dedicated tool helps.

I created a free CFI Duty Time Calculator for exactly this purpose. It lets you enter the start and end times (or duration) of recent and planned flight training sessions (yesterday, today, and tomorrow for example) and calculates your total flight training time inside the current 24-hour window. You can see how many hours remain available before you hit the regulatory limit and whether a proposed additional lesson would put you over. Or if your planned flights for tomorrow based on what you will fly tomorrow will put you over the rolling hours total.

How to use it:

Enter the actual start and stop times for your flights in the relevant training periods that fall inside the rolling 24 hours looking backward from now (or from the end of a planned future session). Then Input the times of completed dual flights and any upcoming lessons you intend to give.

The calculator totals the flight training time and displays the result against the eight-hour ceiling. If you are approaching or exceeding the limit, you see when this will happen and can adjust, move, or reschedule a lesson. You might even have another instructor pick up a flight or you, or delay your flights to build in the required rest.

Instructors who regularly work long days or teach across multiple locations benefit the most. The calculator does not replace professional judgment or official logbook entries, but it gives a fast, reliable way to cross-check your planned or already done flight training events as a CFI before you accept one more lesson.

The tool takes only a minute or two and removes the mental arithmetic and the risk of an honest mistake.

Bookmark the page, use it whenever the schedule looks tight, and keep your flight training hours cleanly under the eight-hour mark.

Click here for a stand-a-lone page that is the calculator.