Calculator inputs
Formula used
Gross Volume = Area × Depth × Number of Beds
Net Soil Volume = Gross Volume × (1 − Rock Fraction)
Effective Dry Density = Dry Bulk Density × Compaction Factor
Dry Soil Weight = Net Soil Volume × Effective Dry Density
Water Weight = Dry Soil Weight × Moisture Content
Moist Soil Weight = Dry Soil Weight + Water Weight
Final Moist Weight = Moist Soil Weight × (1 + Waste Allowance)
Moisture content here is gravimetric, meaning water mass divided by dry soil mass. Compaction factor adjusts the entered dry density before mass is calculated.
How to use this calculator
- Select your preferred unit system.
- Enter the total garden area to be filled or managed.
- Enter average soil depth for the moist layer.
- Type the dry bulk density for your soil blend.
- Add gravimetric moisture content as a percent.
- Enter rock fraction if the bed contains gravel or coarse fragments.
- Adjust compaction if your placed soil will be denser or looser.
- Add waste allowance for handling losses, then enter the number of repeated beds.
- Press the calculate button to see moist weight, dry weight, water weight, density, and Plotly graph.
- Use the CSV or PDF buttons to export your result summary.
Example data table
| Scenario | Area (m²) | Depth (cm) | Dry Density (kg/m³) | Moisture (%) | Rock (%) | Compaction (%) | Beds | Waste (%) | Moist Weight (kg) | Final Weight (kg) |
|---|---|---|---|---|---|---|---|---|---|---|
| Raised bed mix | 8.00 | 15.00 | 1250.00 | 18.00 | 5.00 | 100.00 | 1 | 0.00 | 1,681.50 | 1,681.50 |
| Large landscape fill | 12.00 | 20.00 | 1350.00 | 22.00 | 10.00 | 105.00 | 2 | 8.00 | 7,470.79 | 8,068.46 |
| Four shallow planters | 5.00 | 10.00 | 1180.00 | 12.00 | 0.00 | 95.00 | 4 | 5.00 | 2,511.04 | 2,636.59 |
Frequently asked questions
1) What does moist soil weight mean?
Moist soil weight is the total mass of soil solids plus the water held inside the soil at the entered moisture content. It is useful for hauling, bed filling, lifting limits, and estimating whether supports or containers can safely handle the load.
2) Why is dry bulk density required?
Dry bulk density converts soil volume into dry mass. Once dry mass is known, the water mass can be added from moisture content. Without density, the calculator cannot estimate the actual weight of a moist soil layer or repeated garden beds.
3) Is moisture content measured by volume here?
No. This calculator uses gravimetric moisture content, which means water mass divided by dry soil mass. A value of 20% means the water weighs 20% of the dry soil weight. That method is common in soil testing and engineering work.
4) What does rock or gravel fraction change?
Rock fraction reduces the fine-soil volume used for the weight estimate. This matters when beds include coarse fragments, rubble, or drainage stone. Entering that fraction prevents the calculator from overstating moist soil weight for mixed garden fill materials.
5) When should I change compaction factor?
Use compaction factor when the placed soil will end up denser or looser than the bulk density you entered. A value above 100% increases effective dry density. A value below 100% lowers it. Keep 100% when your density already reflects field conditions.
6) Should I include a waste allowance?
Yes, when trimming, handling losses, spillage, or settling are expected. Waste allowance adds extra moist soil weight and volume above the theoretical need. It is helpful for ordering deliveries, staging labor, or deciding how many trips a wheelbarrow or truck may need.
7) Can I use this for container gardens?
Yes. Enter the surface area and average depth for each container group, then use beds or zones to repeat identical units. The result helps estimate carrying loads, shelf limits, and the delivered mass of a moist planting blend before installation.
8) Which output matters most for transport planning?
The final moist weight with waste allowance is usually the best transport figure because it includes both the water already in the soil and your extra ordering margin. For space planning, also review final volume in cubic meters, cubic feet, or cubic yards.