Weight and Balance CG Calculator
Aircraft weight and balance is a fundamental pre-flight requirement. The center of gravity (CG) must fall within the envelope defined in your Pilot Operating Handbook (POH) for all phases of flight. This calculator applies the standard FAA method: multiply each item's weight by its arm (distance from the datum) to get its moment, sum all moments, sum all weights, then divide total moment by total weight. The result is the CG location in inches from the datum. Enter up to six stations such as basic empty weight, pilot, passengers, fuel, and baggage. Always cross-check the result against your aircraft's actual CG envelope chart before flight. This tool does not substitute for the official weight and balance form required by 14 CFR Part 91.
Enter weight (lb) and arm (in) for each occupied station. Leave unused rows at 0.
| Station | Weight (lb) | Arm (in from datum) |
|---|---|---|
| Basic Empty Weight | ||
| Pilot + Front Pax | ||
| Rear Passengers | ||
| Fuel | ||
| Baggage 1 | ||
| Baggage 2 |
Weight and balance CG formula
Moment(i) = Weight(i) x Arm(i)
CG = Sum of Moments / Sum of Weights
The arm is the horizontal distance (in inches) from the aircraft datum to the center of the item. Multiplying weight by arm gives the moment. Summing moments and dividing by total weight locates the CG. The FAA standard method is described in FAA-H-8083-1B, the Aircraft Weight and Balance Handbook.
Understanding weight and balance
- The datum is an imaginary vertical reference plane defined in the aircraft's type certificate data sheet.
- Forward CG (below the forward limit) reduces elevator authority and increases stall speed.
- Aft CG (beyond the aft limit) reduces longitudinal stability and can make recovery from a stall impossible.
- Fuel weight uses 6 lb/US gal for avgas (100LL) and approximately 6.7 lb/US gal for Jet-A.
- The maximum gross weight and CG envelope are different for takeoff and landing in some aircraft.
Weight and balance CG calculator: frequently asked questions
What is the center of gravity in aviation?
The center of gravity (CG) is the point at which the aircraft's total weight acts. The FAA requires that the CG remain within the forward and aft limits specified in the aircraft's Pilot Operating Handbook (POH) for safe flight.
How is aircraft CG calculated?
CG = Total Moment / Total Weight. The moment for each item is its weight multiplied by its arm (distance from the datum). Sum all moments, sum all weights, then divide. The result is the CG location in inches from the datum.
What happens if the CG is outside limits?
An out-of-limits CG, particularly aft of limits, can make an aircraft unstable and uncontrollable. Forward CG beyond limits increases stall speed and may prevent nose-up rotation. Always check CG before every flight.
What is the datum in weight and balance?
The datum is an imaginary vertical plane from which all arm measurements are taken. It is defined in the aircraft's type certificate data sheet and POH. Arms forward of the datum are positive; some aircraft use negative values for arms aft of datum.
How many items can I add to this calculator?
This calculator supports up to six weight/arm pairs covering the basic empty weight, pilot and passengers, baggage, and fuel. Add each station's weight and arm, and the calculator computes the combined CG instantly.
Official sources
- FAA Aircraft Weight and Balance Handbook (FAA-H-8083-1B): faa.gov.
- 14 CFR Part 91 (General Operating and Flight Rules): ecfr.gov.
Reviewed by the CalculatorHub team, edited by James Graham, 15 June 2026. See our methodology.