How to estimate excavation and earthwork jobs

1. Gather the right documents before you measure

Start with the grading plan, existing topo survey, utility plans, erosion control plan, and the geotechnical report. The geotech report tells you soil types, groundwater depth, and whether rock is likely — the three things that change your production rates the most.

Read the specs for compaction requirements, testing, and what counts as unsuitable material. Note who owns the risk on rock and dewatering; it's often written into the general conditions.

2. Calculate cut and fill volumes

Compare existing and proposed surfaces using the grid, cross-section, or surface-to-surface method. Grid and cross-section methods work by hand on small sites; on anything larger, a digital takeoff from the surfaces is faster and more accurate.

Keep your volumes in consistent units: bank cubic yards (BCY) for material in place, loose cubic yards (LCY) for hauling, and compacted cubic yards (CCY) for fill.

• Subtract topsoil stripping depth across the disturbed area so it isn't counted twice.
• Account for building pads, pavement sections, and subgrade over-excavation separately.
• Treat the structural section (stone base, asphalt, concrete) as its own line, not as part of mass grading.

3. Apply swell and shrink factors

Soil expands when you dig it (swell) and compacts when you place it (shrink). Many clays and loams swell somewhere around 20–40%, sand and gravel less, and blasted rock can swell much more. Use the soil types from the boring logs rather than one number for every job.

A site that 'balances' on paper in bank yards often needs import once shrink is applied. Run the balance in compacted yards before you decide what to import or export.

4. Balance the site and price the haul

Decide what moves on site, what gets exported, and what gets imported. For on-site moves, average haul distance drives whether you use scrapers, articulated trucks, or dozers. For off-site, price by truck cycle time: load, travel loaded, dump, travel back, plus waiting.

Confirm the disposal site, its tipping fees, and whether it accepts your material. Borrow material needs a source, a price per yard, and its own trucking.

5. Take off trenching and underground utilities

Measure trench length by pipe and by depth range — 0–6 ft, 6–10 ft, and so on — because production and shoring change with depth. Add bedding, select backfill, compaction, and spoil handling.

Trenches deeper than 5 feet generally require a protective system under OSHA rules, so carry trench boxes or shoring where the profile calls for it.

6. Build equipment and crew hours from production rates

Divide each quantity by a realistic hourly production rate for the machine doing the work, then adjust for site conditions, operator skill, and weather. Your own historical production is far more reliable than book numbers.

Add mobilization and demobilization, fuel, maintenance, GPS/survey, water trucks for dust, and supervision. Equipment rates should include ownership and operating cost, not just rental.

7. Price or exclude the unknowns

Rock, groundwater, unsuitable soils, contaminated material, and winter conditions should never be buried in a contingency. Price them as unit-price line items or exclude them in writing so the owner knows exactly what's covered.