Enter the area and how deep the fill needs to be at the shallow and deep ends; for an even layer, enter the same depth twice. The calculator averages the depth, adds your compaction allowance, and converts to cubic yards and tons.
Fill dirt calculator
How it works
- Average depth = (shallow depth + deep depth) ÷ 2 (works for an even slope from one end to the other)
- Volume = length × width × average depth ÷ 12 → cubic feet, ÷ 27 → cubic yards
- To order = volume × (1 + compaction allowance)
- Tons = cubic feet × density ÷ 2,000
Default densities from Engineering ToolBox: loose dry dirt 76 lb/cu ft, loose moist dirt 78, dry clay 100 and wet clay 110.
Worked example
A 20 × 10 ft low area that needs 4 in of fill at one end and 8 in at the other, with 15% allowed for compaction:
- Length: 20 ft
- Width: 10 ft
- Depth at the shallow end: 4 in
- Depth at the deep end: 8 in
- Material: Dirt, loose and dry (76 lb/cu ft)
- Extra for compaction and settling: 15%
- Price per ton (optional): $0
The calculator gives:
- Cubic yards: 4.26 cu yd
- Tons (approx.): 4.37 tons at 1.03 t/yd³
- Cubic feet: 115.0 cu ft
- Includes: 15% extra (3.70 cu yd before)
- Metric: 3.26 m³, 3.96 tonnes
The average depth is 6 in, so 100 cu ft (3.7 cu yd). With 15% for compaction, order 115 cu ft, 4.26 cu yd, about 4.4 tons of loose dry dirt.
Material and waste notes
- The compaction allowance is your estimate. How much loose fill shrinks depends on the soil, its moisture and how hard you compact it. Ask your supplier or excavator.
- Bulk density varies with the stone, its size, moisture and how it was loaded. The figures here are general published values (Engineering ToolBox, and IDOT for compacted stone). When you order by the ton, ask the yard for its own conversion and choose “Custom”.
- Fill against a house must slope away from the foundation. The IRC calls for a fall of at least 6 in within the first 10 ft where the lot allows (R401.3).
- Put topsoil on top if you want grass to grow; fill dirt is usually subsoil.
Frequently asked questions
How many tons is a yard of fill dirt?
About 1 ton for loose dry dirt at 76 lb/cu ft (2,052 lb per cubic yard). Wet dirt and clay are heavier: dry clay is about 1.35 tons per cubic yard.
How do I calculate fill dirt for a slope?
Measure the depth needed at the shallow and deep ends, average them, and multiply by the area. Enter both depths in the calculator.
How much extra fill should I order for compaction?
It depends on the soil and how it is compacted. The calculator lets you set the allowance; ask the supplier what their material typically needs.
Sources
- Engineering ToolBox, "Dirt and Mud – Densities" (dirt, gravel, sand and clay, dry and wet)
- International Code Council, 2021 International Residential Code, Chapter 4: R401.3 drainage, Table R401.4.1 presumptive load-bearing values of soils, and Section R403.1 footings
- NIST Special Publication 811, Guide for the Use of the International System of Units (unit conversion factors)
Last reviewed: 25 September 2026. The calculation is covered by automated tests with known answers taken from the sources above. Found an error? Please let us know.