OUTDOOR
How to Estimate an Excavation
Contractor method for estimating excavation: volume, soil type, hauling and access.
Excavation bids fail on the soil and the hauling. The volume is easy math; the rocky ground, the wet spoil and the trucking are where the quote runs over.
THE SHORT ANSWER
How do you estimate an excavation?
Calculate volume (area × depth ÷ 27), price the soil type (loose about $50, moderate $90, rocky $175/cu yd), then add access and hauling by volume. The calculator's 37 cu yd example totals about $4,389.
Calculate the volume
Volume = area × average depth. In cubic yards (US), divide by 27. On sloped sites, take three depth readings and average them — a single reading will miss the real volume.
Price the soil type
Use about $50/cu yd for loose soil, $90 for moderate and $175 for rocky soil as planning allowances. Test the site and price wet clay, groundwater and equipment minimums separately.
Price hauling and access
Estimate hauling at about $15/cu yd, then replace it with the actual trucking and disposal quote. Difficult access adds up to 35% to the digging rate. Use the Excavation Cost Calculator to build the full quote.
Check the total
Your total should land within 10% of the calculator output before markup. Add a utility-locate line item — hitting a line turns a good job into a bad one.