Excavation Calculator

Calculate excavation volume, loose soil after swell, fill requirements, and truckloads for slabs, trenches, footings, and general site prep.

Auto-filled by soil type. Edit to override.

Excavation Volume, Swell, and Truckload Planning

Excavation volume is the starting point, not the final number. Once soil is removed from the ground it loosens and expands, taking up more space in a stockpile or truck than it did in the hole. A job that involves removing 10 cubic yards in the ground will typically produce 12 to 15 cubic yards of loose material depending on soil type. That difference matters when scheduling haul trucks, planning disposal, and budgeting removal costs.

The swell factor accounts for this expansion. Clay expands significantly at around 30%, while gravelly soils expand less at around 12%. Rock is by far the worst at 50 to 60%, which is why rock excavation always costs more than soil work. The soil type selector in the calculator pre-fills a typical swell percentage for each material, and you can override it if your supplier or geotechnical report gives you a more specific figure.

Swell Factors by Soil Type

Soil Type Typical Swell Notes
Clay25-35%Harder to compact; high moisture variation
Sand10-20%Compacts well; low swell compared to other soils
Topsoil20-30%Organic content increases swell variability
Gravelly soil10-15%Lower swell; good drainage properties
Rock50-65%Blasting or breaking required; significantly more volume when loose
Mixed soil20-30%Use 25% as a planning default for unknown mixed sites

Rough Excavation Cost Reference

Excavation costs vary significantly by region, soil type, depth, and access. Labour accounts for 50 to 65% of excavation cost in most markets. These are approximate US ranges for machine excavation as of 2025.

Region States Cost per yd3 (soil) Cost per yd3 (rock)
SoutheastFL, GA, NC, SC, TN$8 - $18$40 - $80
South CentralTX, OK, AR, LA$7 - $16$35 - $75
MidwestOH, MI, IL, IN, WI$10 - $20$45 - $90
Mid-AtlanticPA, VA, MD, NJ$12 - $24$50 - $100
Mountain WestCO, AZ, NV, UT$10 - $22$50 - $95
NortheastNY, MA, CT, RI$15 - $30$60 - $120
West CoastCA, WA, OR$14 - $28$55 - $110

Prices are approximate 2025 averages. Rock excavation costs 3 to 5 times more than soil. Haul-away and disposal fees are additional.

Fill and Compaction

If your project includes backfilling after excavation, the fill quantity needs its own calculation because you are bringing material back in at a different compaction rate than what was excavated. A 10% compaction allowance means ordering 10% more fill material than the net volume requires, since loose fill compacts down as it is placed. For structural backfill around foundations, a geotechnical engineer should specify the fill material and compaction standard.

What Comes After Excavation

Once the dig is done, most projects move straight into base preparation and concrete or asphalt placement. Use the Concrete Slab Calculator for slab work, the Concrete Footing Calculator for foundations, or the Gravel Calculator for base preparation.

Frequently Asked Questions

Swell factor is the percentage by which excavated soil expands once removed from the ground. A hole measuring 10 cubic yards in place will produce 12.5 cubic yards of loose material at 25% swell. This matters because trucks carry loose material, so haul estimates based on in-ground volume will undercount the number of loads needed.
Select the Trench shape and enter length, width, and depth. The formula is length multiplied by width multiplied by depth. For imperial units the result is in cubic feet, which the calculator converts to cubic yards by dividing by 27. Apply the swell factor to get the loose volume for haul planning.
They are separate calculations because they often use different depths and materials. The fill option in the calculator lets you add a fill depth estimate alongside the excavation, with a compaction allowance so you order enough material to hit your target depth after settling.
It is accurate for planning and early budgeting based on your inputs. Actual quantities can change due to site-specific conditions like overdig, soil moisture, buried obstructions, and slope. For structural projects, a site survey and geotechnical assessment will give you more reliable figures.

Excavation Project Planning Checklist

Before breaking ground, confirm utility locates are complete, equipment access is viable, and you have a disposal plan for the excavated material.

Download Checklist (PDF)

Planning use only. See Methodology and Data Sources.View all project checklists →

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Disclaimer

These estimates are for general planning purposes only and should not be used as engineering, structural, or geotechnical guidance. Actual excavation quantities can vary due to soil conditions, moisture, overdig, compaction, access limitations, and field adjustments.

Site preparation and structural work should be verified against local requirements, project drawings, and current code requirements before construction begins.

See our Methodology and Data Sources for details.