Weight & Balance
What the numbers mean — and a CG estimator for when your simulator doesn't give you these values.
Understanding the values
Takeoff Weight TOW / GW
The total weight of the aircraft at the start of the takeoff roll: airframe + fuel + passengers + luggage + cargo. For the A320 family typically 55 000–89 000 kg.
MCDU → PERF INIT shows GW/TOW. Also on the EFB W&B page in Fenix, PMDG, ToLiss, etc.
Zero Fuel Weight ZFW
The aircraft weight with no fuel at all: empty airframe + crew + passengers + cargo. The MZFW limit caps how much payload the aircraft can carry, independent of fuel.
MCDU → FUEL PRED page. Also on the W&B page of add-on aircraft.
Center of Gravity CG % MAC
The aircraft's balance point along the wing chord, in percent. 0% = leading edge of the MAC, 100% = trailing edge. A320 family: 17–40% structural limit, 17–36% for takeoff. Too far forward = hard rotation; too far aft = reduced stability.
Fenix EFB W&B tab. Default MSFS A320 does not show CG — use the estimator below.
Mean Aerodynamic Chord MAC
The "average" front-to-back width of the swept, tapered wing — used as the reference for CG. On the A320 family the MAC is 4.194 m. LEMAC = leading edge, MACTE = trailing edge.
A fixed property of the aircraft — not an input, just the reference for CG position.
Stabilizer Trim THS / STAB
The horizontal stabilizer setting before takeoff, counteracting the CG pitch moment. Aft CG → UP trim; forward CG → DN trim. Entered on the MCDU PERF TAKE OFF page as e.g. UP 1.0.
The takeoff calculator above computes THS automatically once you have CG%.
Flex Temperature FLEX
A higher assumed temperature fed to the engines to reduce thrust, saving engine life on long runways. Must not be lower than actual OAT. No flex = TOGA (full thrust).
Computed by the takeoff calculator. Entered as °C on the MCDU PERF TAKE OFF page.
Where to find CG in your simulator
Fenix A320
EFB → Weight & Balance tab. Shows ZFW, TOW, CG%MAC and stab trim. Load pax, bags and fuel there before departure.
ToLiss A319/A321
Integrated EFB or payload manager displays TOW and CG. MCDU PERF page shows ZFW and GW after loading.
PMDG aircraft
FMC → PERF INIT shows ZFW and GW. The W&B module (where available) shows CG — check the door/fuel panel.
X-Plane (Zibo etc.)
Aircraft menu → Weight & Fuel. CG is shown as % on the loading diagram. Note it before opening the takeoff calculator.
MSFS default A320
Does not show CG%MAC directly. Enter fuel, cargo and pax numbers from the payload screen into the estimator below.
Any simulator
The Fuel & Payload screen gives fuel per tank, cargo weight and pax count. Enter those into the estimator for an approximate CG%.
CG Estimator
Enter fuel per tank, hold payload and passenger count. The diagram and result update live.
Passengers
95 kg / pax incl. baggage
Cargo holds
Empty aircraft
Fuel
For flight simulation only. Values use publicly available approximate reference data. OEW, arm positions and tank capacities vary by MSN, airline configuration and modification standard. Do not use for real-world flight operations.