Aviation Training Experts

Aviation Training Experts™

Alternate Fuel Calculator

Estimate fuel required to fly to an alternate airport using flight time, fuel flow, and optional reserve fuel. This free aviation calculator helps pilots plan IFR fuel requirements more effectively.

Calculate Alternate Fuel

Enter time to the alternate and expected fuel flow to calculate alternate fuel required. You can also add reserve fuel to estimate total fuel needed.

Alternate Fuel Calculator

How It Works

Alternate Fuel:
Fuel = Fuel Flow × Time
Total Fuel Needed:
Total = Alternate Fuel + Reserve Fuel

This calculator estimates the fuel required to fly from the destination area to the alternate airport using a planned fuel flow and time estimate.

What Is Alternate Fuel?

Alternate fuel is the fuel required to continue from the planned destination area to an alternate airport if the destination cannot be used.

In IFR planning, alternate fuel is an important part of total fuel calculation because weather, traffic, or operational conditions may prevent landing at the intended airport.

Why Pilots Use an Alternate Fuel Calculator

Alternate Fuel FAQ

What time should I use for the alternate leg?

Use a realistic estimated time from the destination area or missed approach environment to the alternate airport based on your expected routing and conditions.

Should alternate fuel include reserve fuel?

Alternate fuel and reserve fuel are usually treated separately. Reserve fuel should generally remain protected.

What fuel flow should I use for alternate planning?

Use a realistic fuel flow for the alternate segment based on expected altitude, power setting, winds, and aircraft configuration.

Is this calculator enough for legal dispatch planning?

No. This calculator is a planning aid. Always use approved aircraft data, company procedures, and applicable regulatory requirements.