Weight & Balance Calculator
Calculate loaded weight, total moment, and center of gravity for your aircraft. Select an aircraft template or enter values manually.
Last reviewed: July 2026
Source: Cessna 172S POH, Revision 4 (2006), Part No. 172SPHBUS-00 | Serial range: 172S8001 and subsequent
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Why Weight & Balance Matters
Weight and balance is one of the most important preflight calculations a pilot performs. An aircraft that is within its weight limits but outside its CG limits can be uncontrollable — particularly during takeoff rotation and recovery from unusual attitudes.
The center of gravity affects:
- Stability: A forward CG makes the aircraft more stable but requires more back pressure to rotate and climb. An aft CG reduces stability and increases the risk of a stall that cannot be recovered.
- Control authority: At the aft CG limit, the elevator may not have enough authority to recover from a stall.
- Performance: An overloaded aircraft requires more runway, climbs more slowly, and has reduced range.
The FAA requires pilots to verify weight and balance before every flight under 14 CFR 91.9. It is not optional.
Limitations
- This calculator uses arms from published POH data for the selected aircraft template. Your specific aircraft's actual arms may differ due to modifications, equipment changes, or reweighing.
- Always use the empty weight and arm from your aircraft's current approved weight and balance report — not a generic value.
- Fuel arm values assume standard tanks at the stated fill level. Variable-arm fuel systems (where the arm changes as fuel burns) are noted where applicable.
- This calculator does not account for unusable fuel weight in the moment calculation — unusable fuel is included in the basic empty weight.
- Baggage area limits are structural limits — exceeding them can damage the aircraft even if the total weight and CG are within limits.
This result is for educational and planning purposes only. Always verify against the current approved weight and balance data for your specific aircraft (POH/AFM, current equipment list, and current empty weight and balance report). Read our full Safety Disclaimer.
Frequently Asked Questions
Weight and Balance in Depth
Weight and balance is the process of confirming, before every flight, that the aircraft is loaded within both its maximum weight limit and its center-of-gravity range. These are two separate checks that must both pass: an aircraft can be under gross weight yet dangerously out of balance, or perfectly balanced yet overweight. Getting both right is a legal requirement and, more importantly, a direct determinant of whether the aircraft will handle predictably.
The physics is straightforward but unforgiving. Every item aboard — fuel, passengers, baggage — has a weight and a location, and the aircraft balances around a point that the combined loading determines. Load too much weight aft and the aircraft becomes unstable and difficult to recover from a stall; load too far forward and it may be impossible to flare for landing. This calculator sums the moments so you can see exactly where your loading falls.
Step-by-Step: How the Calculation Works
The calculation multiplies each item weight by its arm — the distance from a reference datum — to produce a moment. Summing all the weights gives total weight, and summing all the moments and dividing by total weight gives the center of gravity. This CG is then compared against the forward and aft limits published in the aircraft flight manual for that total weight.
The datum and arms come from your specific aircraft weighing record, because empty weight and empty-weight CG differ from airframe to airframe even within one model. Loading each station accurately — front seats, rear seats, baggage, and fuel at its arm — and comparing the result against the envelope is the only reliable way to confirm a legal, safe load. The calculator performs the arithmetic; the accuracy depends on using your airplane's real numbers.
More Worked Examples
Example 1 — A routine two-person load
Empty weight 1,500 lb at arm 39 in, two front-seat occupants totaling 340 lb at arm 37 in, 40 gallons of fuel (240 lb) at arm 48 in, and 30 lb of baggage at arm 95 in. Total weight is 2,110 lb; total moment is the sum of each weight times its arm, and dividing gives a CG that must fall within the published forward and aft limits at 2,110 lb.
Example 2 — Watching the aft limit
Add two rear-seat passengers at 320 lb combined at arm 73 in and increase baggage to 100 lb. The extra aft weight moves the CG rearward. Even if total weight stays under gross, the CG may now approach or exceed the aft limit, requiring you to move baggage forward or reduce the aft load before the flight is legal and safe.
Pilot Decision-Making Context
Weight and balance decisions are made on the ground because they cannot be undone in the air. If the numbers place you outside the envelope, the options are concrete: burn or offload fuel, move or remove baggage, or leave a passenger behind. There is no technique that compensates for an out-of-limits load, which is why the check is a non-negotiable part of preflight for every flight, not just heavy ones.
A subtler point is that CG moves during flight as fuel burns off. A load that is legal at takeoff can drift toward a limit as the tanks empty, particularly when the fuel arm is well forward or aft of the CG. Checking both the takeoff and the projected landing loading ensures the aircraft stays within limits for the entire flight, not just the moment you leave the ramp.
More Questions Answered
Can I fly if I am under gross weight but outside the CG range?
No. Weight and balance are independent limits and both must be satisfied. An in-limits weight with an out-of-limits CG is unairworthy and can be dangerous to control.
Why does CG change during the flight?
As fuel burns, weight leaves the aircraft at the fuel tanks' arm, shifting the CG toward the remaining load. If the fuel arm differs from the overall CG, the balance point migrates during the flight.
Do I use standard passenger weights or actual weights?
For light general aviation aircraft, use actual weights whenever possible. Standard average weights are designed for larger operations and can understate the true load in a small airplane.
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