Aircraft Weight and Balance Calculator
Before every flight a pilot must confirm the aircraft is loaded within its approved weight and centre of gravity envelope. The method sums the moment (weight times arm) of every item, divides the total moment by the total weight, and gives the centre of gravity. This calculator handles four loading stations: empty aircraft, front seats, rear seats or baggage, and fuel. It is a calculation aid only. Always check the result against the limits and arms in your aircraft's approved flight manual.
Weight and balance formula
moment of each item = weight * arm
total weight = sum of weights
total moment = sum of moments
centre of gravity = total moment / total weight
The centre of gravity is the weighted average position of all the loads. Compare the total weight to the maximum gross weight and the CG to the forward and aft limits in your flight manual.
Worked example
Empty 1,500 lb at 39 in (58,500 lb-in), front 340 lb at 37 in (12,580), rear 170 lb at 73 in (12,410), fuel 180 lb at 48 in (8,640). Total weight = 2,190 lb. Total moment = 92,130 lb-in. CG = 92,130 / 2,190 = 42.07 in from datum. Confirm this falls inside your aircraft's CG envelope.
Weight and balance: frequently asked questions
How is centre of gravity calculated?
Each item of weight has a moment equal to its weight multiplied by its arm (distance from the reference datum). Total weight is the sum of all weights, and total moment is the sum of all moments. The centre of gravity equals total moment divided by total weight. It must fall within the limits in your aircraft's approved flight manual.
What is the arm and datum?
The datum is a fixed reference point on the aircraft, defined by the manufacturer, from which all arms are measured. The arm is the horizontal distance from the datum to the centre of a weight, in inches. Weights ahead of the datum may use negative arms depending on the manufacturer's convention. Use the arms from your aircraft's weight and balance documents.
Why does weight and balance matter?
Loading outside the approved weight or centre of gravity envelope can make an aircraft uncontrollable, unable to climb, or unable to recover from a stall. Federal aviation regulations require the pilot to ensure the aircraft is loaded within limits before flight. This calculator does the arithmetic; the limits and arms come from your aircraft documents.
Does this replace the POH?
No. This is a calculation aid only. You must verify total weight is within the maximum gross weight and the centre of gravity is within the forward and aft limits using your specific aircraft's Pilot Operating Handbook or approved flight manual and current weighing data. Never fly on a figure you have not confirmed against the POH.
Official sources
- U.S. Federal Aviation Administration: Aviation handbooks and manuals (Aircraft Weight and Balance Handbook, FAA-H-8083-1).
- U.S. Federal Aviation Administration: FAA regulations and handbooks. Use the arms and limits from your aircraft's approved flight manual.
Reviewed by the CalculatorHub team, edited by James Graham, 19 June 2026. See our methodology.