How Per Diem Works for Flight Crew
Written by a working flight attendant, creator of CrewPay
A plain-language guide to TAFB, per diem rates, and how crew meal and expense pay adds up over a trip.
What per diem actually is
Per diem is the hourly allowance most airlines pay crew members while they are away from their home base. It exists to cover meals and incidental costs on the road, and it is usually paid on top of flight pay rather than as part of it. Because it is tied to time rather than to flying, a trip with long layovers can earn noticeably more per diem than a trip that flies the same number of hours with short sits.
Most contracts express per diem as a dollar amount per hour of Time Away From Base, often called TAFB. Some carriers use one rate for domestic flying and a higher rate for international flying, and a few adjust the international rate by destination. Your collective bargaining agreement or company policy manual is the only reliable source for your exact numbers.
How TAFB is measured
TAFB normally starts at your scheduled report time for the first leg of a pairing and ends at the scheduled or actual release time after your last leg back at base. That means hotel time, sit time between legs, and time spent deadheading all count. A three-day trip that reports at 6:00 on day one and releases at 18:00 on day three has 60 hours of TAFB, even if you only flew 14 hours.
Some contracts calculate TAFB from the actual times and some from the scheduled times, and many use whichever is greater. Delays can therefore increase per diem on a trip, which is one reason the final number on your pay statement may not match the bid package exactly.
Doing the math
The basic formula is simple: TAFB hours multiplied by your per diem rate. At a rate of $2.25 per hour, 60 hours of TAFB produces $135.00 of per diem. At 80 hours the same rate produces $180.00. In the CrewPay calculator, enter your rate once in the Per Diem Rate box and your trip's hours in each Total Per Diem box, and the per diem is folded into every Estimated Trip Pay subtotal automatically.
If your trip includes minutes, convert them to a decimal before entering them. Thirty minutes is 0.5 hours, fifteen minutes is 0.25 hours, and forty-five minutes is 0.75 hours. Small rounding differences rarely change the result by more than a few cents, but converting carefully keeps your estimate honest.
Tax treatment and why it matters
In many cases per diem is paid partly or fully tax-free up to limits set by the tax authority, while flight pay is taxed as normal wages. That makes a dollar of per diem worth more in your pocket than a dollar of flight pay for many crew members. Rules vary by country and situation, so talk to a tax professional who understands aviation pay before relying on any assumption.
Using per diem when bidding
When you compare pairings, look at both the credit hours and the TAFB. A trip with fewer credit hours but a long layover in an expensive city can still come out close to a higher-credit trip once per diem is added. Laying two or three trips side by side in the calculator makes these trade-offs visible in seconds, which is far easier than juggling the numbers in your head at the gate.
Remember that the calculator is an estimator. It uses only the numbers you type, and it cannot know about guarantees, overrides, or company-specific rules. Always confirm the final figures against your own contract.
Try it yourself
Open the CrewPay Trip Calculator to price a trip or compare up to three. Read the disclaimer for how estimates work.