Centre of Gravity and Moments Calculator

Calculate total mass, longitudinal moment, centre of gravity and margins against an entered CG envelope and MTOW.

A component-based longitudinal mass-properties check for one declared aircraft datum.

Start here

  1. Choose one aircraft datum and enter the forward/aft CG limits and maximum mass.
  2. Add each component with its mass and signed distance from that datum, then choose Calculate.
  3. Read total mass, calculated CG and the margins to both CG limits.
How to read the results

Use the same datum and arm direction for every row. The tables show how each mass contributes to the total moment.

Local calculation: values are processed in your browser. Calculation inputs are not transmitted. Optional profiles are stored only in this browser.
Optional aircraft profile: Manual values
Active profile: Manual values
mm
mm
kg

Configuration components

Use masses and longitudinal arms from one declared aircraft datum.

ComponentMass (kg)Arm (mm)Remove

Planning output only. Verify assumptions and results against authoritative data, manufacturer information, approved procedures, test evidence and competent engineering or regulatory review before use.

Calculation basis

Each component moment is mass x longitudinal arm. Total moment divided by total mass gives the longitudinal centre of gravity relative to the entered datum.

Limitations and verification

  • All arms must use the same datum and sign convention.
  • Assesses one longitudinal axis only; lateral CG, vertical CG, fuel movement, structural loading and dynamic stability are not modelled.
  • Use measured configuration masses and the approved CG envelope for the exact aircraft configuration.

Version and review status

Formula set: v1.2
Staging review date: 17 August 2026
Status: Staging beta pending user acceptance and cross-browser checks.