Weight and Balance Calculator
Why Center of Gravity Is Non-Negotiable
An aircraft loaded outside its approved center of gravity range doesn't just handle differently — it can become unrecoverable in certain phases of flight. A CG too far forward increases stall speed and can make rotation on takeoff difficult or impossible; too far aft reduces longitudinal stability and can make the aircraft uncontrollable at high angles of attack. Every pre-flight weight and balance check exists to rule that out before the aircraft ever leaves the ramp.
The Formula
Weight and balance is built from a simple idea applied to every loaded station in the aircraft: weight multiplied by its distance from a reference datum gives a moment, and the sum of all moments divided by the sum of all weights gives the center of gravity.
Total Weight = Σ Station Weights
Total Moment = Σ (Station Weight × Station Arm)
CG = Total Moment ÷ Total Weight
This calculator applies that formula across five common stations — empty aircraft, front seats, rear seats, baggage, and fuel — and, when forward and aft CG limits are supplied, reports directly whether the resulting CG falls within the approved envelope. Fuel weight is estimated at 6 lb per gallon, the standard approximation for aviation gasoline.
Where This Calculation Matters
- Every flight, every time — weight and balance is a required part of pre-flight planning, not an occasional check reserved for unusual loads.
- Passenger and baggage trade-offs — deciding where to seat passengers or stow baggage to keep the loaded CG within limits, especially on aircraft with a narrow CG envelope.
- Fuel burn-off effects — CG shifts as fuel burns, since fuel tanks sit at a fixed arm; some aircraft need a burn-off check for long flights.
- Flight school and rental checkouts — renters and student pilots are routinely required to show a completed weight and balance before a rental or checkride.
Visualizing the CG Envelope
Simplified illustration of a CG envelope: the calculated CG must fall between the forward and aft limits published in the aircraft's POH.
How to Use This Calculator
- Enter the empty aircraft weight and its arm (both found in the aircraft's weight and balance report).
- Add weight and arm figures for front seats, rear seats, and baggage as applicable to your load — leave any unused station blank.
- Enter fuel in gallons and the fuel station's arm; the calculator converts fuel to weight automatically.
- Optionally enter the forward and aft CG limits from the POH to get an immediate within-limits or outside-limits result.
- Select Calculate to see total weight, total moment, and the resulting CG in inches from the reference datum.
Related Calculations
Once loading is confirmed, check Runway Length requirements for the loaded weight, or review Landing Distance since a heavier, more aft-loaded aircraft typically needs more runway.