How to use this calculator
- Enter empty weight and arm. Use current basic empty weight records.
- Enter station loads. Add occupant, fuel and baggage weights with their station arms.
- Enter CG limits. Use the forward and aft limits for the weight/configuration being checked.
- Read CG margins. Compare loaded CG with both limits.
How it works
Each station moment is weight x arm. Loaded CG is sum(moment) / sum(weight). The page then reports margin to the entered forward and aft CG limits.
Use it before Va weight adjustment, stall speed and climb gradient.
Worked example
Verified against the live calculator
A 1,500 lb empty aircraft at 39 in, two 170 lb occupants, 240 lb of fuel and 50 lb of baggage gives a loaded weight near 2,130 lb and a CG near 46 in for the default arms.
Frequently asked questions
How is aircraft CG calculated?
Total each station moment as weight times arm, sum all moments, then divide total moment by total weight.
What is a station arm?
Arm is the distance from the aircraft datum to that item or station.
Can optional station weights be zero?
Yes. Set a station weight to zero if that station is not loaded.
Does this prove the airplane is legal to fly?
No. You must use the current aircraft records, approved envelope, loading instructions and maximum weight limits.
Method & assumptions
- Uses station moment arithmetic only.
- Does not validate maximum gross weight, fuel burn sequence, baggage placards, CG envelope shape or aircraft-specific loading rules.