Gravel and Fill Calculator
Calculate cubic yards of gravel, sand, or fill material to order with an adjustable compaction factor for crushed stone, loose fill, or roller-compacted aggregate.
The in-place compacted depth your plans call out.
1.20 default for crushed-stone sub-base. 1.10-1.15 for loose fill (sand, topsoil). 1.25-1.30 for heavily-compacted aggregate or pads.
About this tool
Aggregate suppliers sell crushed stone and fill by the loose cubic yard at the truck. The number that matters on the job is the compacted in-place volume, which is always smaller because the material packs down under a plate compactor or roller. Order based on in-place volume and you come up short. Order based on loose volume from your geometry and you sometimes come up long. The compaction factor bridges the gap.
Enter the length and width of the area in feet and the finished depth in inches. The depth is the in-place compacted depth, which is what your plans call out. The compaction factor multiplier converts that in-place volume to the loose-yard volume your supplier needs to deliver.
The default 1.20 covers most crushed-stone sub-base under a slab or driveway. Drop to 1.10-1.15 for loose fill (sand, topsoil) that is screeded but not heavily compacted. Push to 1.30 for heavy roller-compacted aggregate where the in-place density approaches Proctor maximum. See the methodology page for where these defaults come from.
How it works
Volume = length × width × depth, with depth converted from inches to feet. Divide by 27 to convert cubic feet to cubic yards. Multiply by the compaction factor to get the loose volume to order from the supplier.
Compaction factors reflect observed shrinkage in standard sub-base materials reported in AASHTO T 180 (Modified Proctor) and the FHWA Soils and Foundations Reference Manual. The 1.20 default for crushed stone corresponds to typical 80-85% in-place density relative to loose density.
Examples
A 20×12 driveway sub-base at 4 inches finished depth. In-place volume is 2.96 yd³; with the 1.20 compaction factor, 3.56 yd³ is needed at the truck. Round up at the supplier; most yards deliver in 1 yd³ minimums.
A 30×30 pole-barn pad at 6 inches, heavily compacted under expected loading. The 1.25 factor accounts for repeated rolling compaction; pads under repeated heavy loads need this higher factor.
A 100-foot utility trench with 8 inches of sand bedding. Sand compacts less than crushed stone, so the 1.10 factor is appropriate.
When to use
Use this for sub-base under a slab or driveway, trench bedding for utility runs, structural fill for a building pad, or landscape fill where you specify a finished compacted depth. Pair with the concrete yardage calculator when the gravel is sub-base for a slab; both quantities usually share a delivery ticket. For engineered fill on a permit set, follow the geotechnical report's compaction spec, not this default.
Related concepts
- AASHTO T 180 : Modified Proctor compaction test
- Compaction factor practice
Frequently asked questions
Why is the ordered amount more than the in-place amount?
Aggregate is sold loose at the truck. It compacts down to a smaller volume in place. The compaction factor multiplies the in-place volume to give the loose volume the supplier needs to deliver so you end up with the correct compacted depth.
How do I pick the right compaction factor?
1.10-1.15 for loose fill (sand, topsoil) that is screeded but not heavily compacted. 1.20 for typical crushed-stone sub-base. 1.25-1.30 for heavily compacted aggregate or pads under repeated heavy loading.
What about settling over time?
This calculator covers initial compaction during placement. Long-term settlement under structural loads is a geotechnical question and depends on the specific material and load. Engineered jobs need a compaction test on the placed material, not just a rule of thumb.
Sources
- AASHTO T 180, Standard Method of Test for Moisture-Density Relations of Soils (Modified Proctor)
(primary, accessed Apr 16, 2026)
American Association of State Highway and Transportation Officials standard for compaction testing, underlying the 1.20-1.30 compaction factor ranges.
- FHWA Soils and Foundations Reference Manual
(primary, accessed Apr 16, 2026)
Federal Highway Administration geotechnical reference for sub-base design and placement.
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