Ballast Calculator
Calculate tons of ballast stone for a track bed or foundation using its 1.4 tons per cubic yard density, plus total material cost.
How this calculator works
Ballast stone is sold by weight but measured by volume, so this calculator converts your length, width, and depth into cubic yards, then multiplies by ballast’s typical density of 1.4 tons per cubic yard to get the tons you need to order.
Formula: Cubic yards = (Length ft × Width ft × Depth ft) ÷ 27. Tons = Cubic yards × 1.4.
Worked example
A 20 ft × 10 ft foundation or bed section at a 6-inch depth:
- Depth in feet: 6 ÷ 12 = 0.5 ft
- Cubic yards: (20 × 10 × 0.5) ÷ 27 ≈ 3.7037 yd³
- Tons: 3.7037 × 1.4 ≈ 5.19 tons
- At $50/ton, that’s $259.26 before waste.
Coverage reference
| Area | Tons needed (at 6 in) |
|---|---|
| 10 ft × 5 ft | 1.30 tons |
| 20 ft × 10 ft | 5.19 tons |
| 40 ft × 20 ft | 20.74 tons |
How to measure your area
Measure the length and width of the bed or foundation footprint in feet, using the full loose depth called for in your spec since ballast isn’t a compacted material in the way a fines-based base is. On a track-bed job, measure the ballast section width beyond the tie ends, since ballast typically extends past the rail structure on each side.
Frequently asked questions
What is ballast stone used for?
Ballast is a large, coarse, clean crushed stone traditionally used to support railway track beds, where it distributes the load from ties and rails while letting water drain freely. It's also used for foundation and heavy structural fill work, and as the loose stone layer on ballasted roof systems.
Why is ballast used on railway tracks specifically?
Its large, angular particles interlock under vibration and heavy cyclical loading in a way that finer aggregate can't, while the open void space between stones lets rainwater drain instantly instead of pooling under the rails and undermining the bed over time.
How is ballast different from #2 stone?
They're close cousins — both run about 1.4 tons per cubic yard and are similarly sized — but ballast is the term used specifically for railway and heavy foundation applications, while #2 stone is the more general name for the same size class used in drainage and construction entrances.
What depth of ballast is used under a railway tie or heavy foundation?
Track ballast beds are typically 8-12 inches deep under the ties, while ballast used as general heavy foundation fill often matches whatever depth the structural engineer specifies for that particular load.
Do I need a filter layer under ballast?
In track and heavy drainage applications, yes — a layer of finer material or a geotextile fabric is often placed beneath ballast to keep it from mixing into the softer subgrade below over years of vibration and load cycling.
Should I add waste when ordering ballast?
Yes, a 10% buffer covers an uneven excavated base and the spillage that comes with handling such a coarse, heavy stone.
Estimates only. Verify quantities with your supplier before purchasing.