Ballast Requirement Calculator

Work out ballast requirement instantly with clear inputs, formula shown and shareable results.

About Ballast Requirement Calculator

Ballast is sized from the moment equation: the added weight must shift the whole aircraft's CG from where it is to where you want it. Solving W x (target - CG) = ballast x (arm - target) gives the mass needed at a chosen station, which is why a station far from the target needs much less ballast.

Formula

Ballast mass

Ballast = W x (target CG - current CG) / (ballast arm - target CG)

Worked example

With the default values below, Ballast Requirement Calculator returns Ballast required of 94.14. Change any input above and every figure here is recalculated in your browser.

Inputs used

Current centre of gravity: 2.02 m
Target centre of gravity: 2.15 m
Aircraft weight: 1,050 kg
Ballast station arm: 3.6 m

Results

Ballast required: 94.14 kg
Weight after ballast: 1,144.14 kg
Resulting centre of gravity: 2.15 m
Ballast position: Add ballast at the stated station

Step by step

1Values used
2Ballast mass
3Ballast required= 94.14 kg
4Weight after ballast= 1,144.14 kg
5Resulting centre of gravity= 2.15 m
6Ballast position= Add ballast at the stated station

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Aviation results are planning estimates only. Always verify take-off, landing, fuel, weight and balance figures against the certified Aircraft Flight Manual, current performance charts and applicable aviation regulations before flight.

Frequently Asked Questions

Why does the ballast arm matter so much?

Leverage. Ballast placed close to the target CG has almost no effect, so the denominator shrinks and the required mass grows very quickly.

Must ballast be secured and documented?

Yes. Ballast must be permanently or positively secured, placarded, and entered in the weight and balance record — loose ballast is a hazard in turbulence.