Excavation Calculator

Estimate excavation volume from length, width and depth, with cubic yards, cubic metres, loose spoil, truckload checks, cost estimate and a printable dig or quote note.

Excavation volumeExcavation Calculator uses the declared inputs to produce a transparent default result. Excavation length: 30 ft; Excavation width: 12 ft; Excavation depth: 18 in; Matching sections: 1; primary comparison: 30 and 12.

Excavation lengthftExcavation widthftExcavation depthinMatching sectionsLoose spoil swell%Truck capacityyd³/load

Live math canvas

Your numbers, formula and explanation together

Excavation Calculator: 131 cubic yards with cubic-metre, loose-spoil, truckload and cost checks. Excavation Calculator uses the declared inputs to produce a transparent default result. Excavation length: 30 ft; Excavation width: 12 ft; Excavation depth: 18 in; Matching sections: 1; primary comparison: 30 and 12.

Formula applied

The exact method behind this answer

CalculationTime keeps the method visible so the number can be checked instead of blindly trusted.

Depth feet = excavation depth inches ÷ 12. Bank cubic feet = length feet × width feet × depth feet × number of sections. Bank cubic yards = bank cubic feet ÷ 27. Bank cubic metres = bank cubic yards × 0.764554857984. Loose spoil cubic yards = bank cubic yards × (1 + swell percent ÷ 100). Truckloads = ceiling(loose spoil cubic yards ÷ truck capacity cubic yards). Cost estimate = loose spoil cubic yards × rate per cubic yard.

Apply the formulaDepth feet = excavation depth inches ÷ 12. Bank cubic feet = length feet × width feet × depth feet × number of sections. Bank cubic yards = bank cubic feet ÷ 27. Bank cubic metres = bank cubic yards × 0.764554857984. Loose spoil cubic yards = bank cubic yards × (1 + swell percent ÷ 100). Truckloads = ceiling(loose spoil cubic yards ÷ truck capacity cubic yards). Cost estimate = loose spoil cubic yards × rate per cubic yard.131 cubic yards with cubic-metre, loose-spoil, truckload and cost checksExcavation Calculator uses the declared inputs to produce a transparent default result. Excavation length: 30 ft; Excavation width: 12 ft; Excavation depth: 18 in; Matching sections: 1; primary comparison: 30 and 12.

Your live breakdown

Current inputs in the calculation

These values come from the controls above and update when the calculator changes.

Excavation length: 30 ft
Excavation width: 12 ft
Excavation depth: 18 in
Matching sections: 1
Loose spoil swell: 25 %
Truck capacity: 10 yd³/load
Excavation or disposal rate: 35 $/yd³

Resulting answer

131 cubic yards with cubic-metre, loose-spoil, truckload and cost checks

Excavation Calculator uses the declared inputs to produce a transparent default result. Excavation length: 30 ft; Excavation width: 12 ft; Excavation depth: 18 in; Matching sections: 1; primary comparison: 30 and 12.

Answer: 131 cubic yards with cubic-metre, loose-spoil, truckload and cost checks
Live support: Excavation Calculator uses the declared inputs to produce a transparent default result. Excavation length: 30 ft; Excavation width: 12 ft; Excavation depth: 18 in; Matching sections: 1; primary comparison: 30 and 12.

Assumptions used

What this answer assumes

Best for trench digs, patio or driveway cut-outs, garden excavation, footing prep, haul-off notes, skip-bin planning, contractor quote checks and classroom volume worksheets where bank volume and loose spoil need to stay separate.

The calculator treats each section as a rectangular excavation with an average depth entered by the user.
Depth is entered in inches and converted to feet before volume is calculated.
Loose spoil swell is shown separately because excavated soil, clay, gravel and mixed fill can occupy more space after digging than it did in the ground.
Truckload and cost outputs are planning checks only; real loading, road limits, skip sizes, access, dumping rules and minimum charges can change the job.
This is a quantity estimate, not an excavation safety, utility-location, shoring, drainage, geotechnical or permit approval.

Master’s Tip

How to use the result well

Master’s Tip: print both bank volume and loose spoil volume. The measured hole and the material hauled away are not the same thing, and mixing those two numbers is a common reason excavation quotes miss truck space or disposal cost.

Printable record

What belongs in the saved calculation

Save the inputs, result, formula, assumptions, page URL and date together so the calculation can be reviewed later.

Excavation length: 30 ft
Excavation width: 12 ft
Excavation depth: 18 in
Matching sections: 1

Embeddable calculator

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Copy a clean iframe version with the required CalculationTime attribution link built in.

Formula

Depth feet = excavation depth inches ÷ 12. Bank cubic feet = length feet × width feet × depth feet × number of sections. Bank cubic yards = bank cubic feet ÷ 27. Bank cubic metres = bank cubic yards × 0.764554857984. Loose spoil cubic yards = bank cubic yards × (1 + swell percent ÷ 100). Truckloads = ceiling(loose spoil cubic yards ÷ truck capacity cubic yards). Cost estimate = loose spoil cubic yards × rate per cubic yard.

Worked example

For one 30 ft by 12 ft excavation at 18 inches average depth, depth = 18 ÷ 12 = 1.5 ft. Bank volume = 30 × 12 × 1.5 = 540 ft³, or 20 yd³. With 25% swell, loose spoil is 25 yd³, about 3 truckloads at 10 yd³ per load.

Professional note

Regional and unit assumptions

Standard or basis: rectangular volume arithmetic with 27 cubic feet per cubic yard and 1 cubic yard ≈ 0.764554857984 cubic metres. Soil swell is job-specific; confirm the swell factor, truck capacity, disposal rules, utility locating, shoring and safety requirements with the contractor or local authority.

Assumptions and limitations

The calculator treats each section as a rectangular excavation with an average depth entered by the user.
Depth is entered in inches and converted to feet before volume is calculated.
Loose spoil swell is shown separately because excavated soil, clay, gravel and mixed fill can occupy more space after digging than it did in the ground.
Truckload and cost outputs are planning checks only; real loading, road limits, skip sizes, access, dumping rules and minimum charges can change the job.
This is a quantity estimate, not an excavation safety, utility-location, shoring, drainage, geotechnical or permit approval.

Methodology & Accuracy

How this calculator is checked

CalculationTime pages are built around visible arithmetic: the formula, assumptions, worked example and practical limitations are shown so the result can be checked rather than simply trusted.

Formula used

Standard or basis

Where a calculator follows a named legal, trade or industry standard, that standard is cited visibly. Otherwise the page uses transparent general arithmetic and states its limits.

Master's Tip

Questions

How do I calculate excavation volume?

Multiply excavation length by width by average depth. Convert depth to feet first if it is measured in inches, then divide cubic feet by 27 to get cubic yards.

What is bank volume in excavation?

Bank volume is the volume of material in the ground before it is dug. Loose spoil volume is usually larger because soil expands when excavated and disturbed.

Why does the calculator include swell percent?

Swell percent estimates how much extra space loose excavated material may occupy. It helps compare the measured hole with truck, skip or disposal capacity.

Can this estimate trench or footing excavation?

Yes for a simple rectangular trench, pit or pad if you enter the length, width and average depth. Irregular shapes should be split into sections and checked separately.

What should I print for an excavation quote?

Print the length, width, average depth, number of sections, bank cubic yards, loose spoil allowance, truckload check, rate, formula, date, page URL and site notes.

Calculation note

Excavation estimating uses simple volume math, but the useful job record separates the measured in-ground cut from loose material that must be moved, loaded and disposed of. That distinction keeps the calculation practical instead of just geometric.

The hole is measured before the truck is ordered

Length, width and average depth describe the bank volume of the planned cut. That is the geometric starting point for the excavation record.

Loose soil changes the hauling question

Once material is dug, it is no longer packed in place. Showing swell separately helps a homeowner or contractor compare the planned cut with truck, skip and disposal capacity.

A printed excavation note keeps safety outside the arithmetic

The printout is useful for quantities and quote conversations, but it does not replace utility locating, shoring, access planning, drainage design or local permit checks.

Sources and further readingNIST Handbook 44 Appendix C — General Tables of Units of Measurement BIPM — The International System of Units OSHA — Trenching and excavation safety