How to use this calculator
- Choose the mode. Use target-weight mode when you already know the desired ballast, or counterweight mode when a load and arm are known.
- Enter the arms. Measure load arm and ballast arm from the same pivot, axle or balance point.
- Pick the material. Use a density preset or enter the density of the actual fill, block or plate material.
- Set a standard piece weight. Enter the size of one suitcase weight, plate or block.
- Review the rounded result. Use the required ballast, volume and rounded piece count as planning numbers before checking real ratings.
How it works
The counterweight mode uses a simple static moment balance: required ballast = load mass x load arm x (1 + margin/100) / ballast arm Target-weight mode skips the moment balance and uses the entered target mass directly. In both modes, ballast volume is: volume = ballast mass / material density
For vehicle and fleet loading, pair this with the truck payload calculator, corner weight calculator or stopping distance calculator. For dense plate or block takeoffs, use the metal weight calculator.
Worked example
Verified against the live calculator
A 1,200 lb load at a 5 ft arm, balanced by rear
ballast at a 4 ft arm with a 10% moment margin,
needs 1,650 lb of ballast. With 100 lb
standard weights, that rounds to 17 pieces or
1,700 lb actual ballast. Concrete at about
150 lb/ft3 would occupy about 11 ft3.
Frequently asked questions
How do you calculate counterweight ballast?
For a simple static moment screen, required ballast = load mass x load arm / ballast arm. This calculator can also add an entered moment margin before dividing by the ballast arm.
How do you estimate ballast volume?
Ballast volume is mass divided by density. Concrete, cast iron, steel, water and loose sand or gravel are included as presets, and custom density can be entered when you know the actual material.
Is this a tractor ballast recommendation?
No. It is a weight, volume and moment calculator. Real tractor, loader, forklift, hitch and vehicle ballast decisions still need manufacturer limits, axle and tire ratings, scale weights, terrain and operator-manual guidance.
Why does the standard weight count round up?
Suitcase weights, plates and blocks are discrete pieces. The calculator rounds up to the next whole piece so the actual ballast meets or exceeds the calculated target.
Ballast density chart
These density presets are typical planning values. Use a measured or supplier value when the ballast block, liquid fill, aggregate moisture or steel stack is known.
| Material | kg/m3 | lb/ft3 | Use note |
|---|---|---|---|
| Concrete | 2,400 | 150 | typical normal-weight concrete |
| Cast iron | 7,200 | 449 | typical cast-iron counterweights |
| Steel plate | 7,850 | 490 | typical carbon steel plate |
| Water | 1,000 | 62 | water ballast before tank allowance |
| Sand / gravel | 1,600 | 100 | loose dry aggregate estimate |
Method & assumptions
- Load arm and ballast arm must be measured from the same pivot, axle or balance point.
- The moment calculation is static and planar; it does not model rollover, dynamic braking, slope, traction, loader geometry, hitch leverage or tire loading.
- Standard weight count is rounded up to whole pieces. Actual installed ballast still needs brackets, pins, retainers and rated mounting points.
- Real equipment work still needs the operator manual, manufacturer ballast tables, axle ratings, tire ratings, hitch limits, scale weights and site conditions.