Excavation Calculator
Estimate how much soil comes out of a hole, trench or basement dig. Enter the dimensions and soil type to get the bank (in-place) volume, the loose volume after swell, the weight, the number of truck loads and, if you add your rates, the haul cost.
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Sloped sides add volume. Trench ends are treated as vertical.
Increase from bank (in place) to loose volume.
Bank to compacted fill; negative for rock.
Single-axle ~5, tandem ~10–14, tri-axle ~16–18 cu yd.
Legal payload; heavy soils fill the weight before the box.
Your hauler's price per truck load, incl. dump fee if any.
Per bank cu yd (or m³).
How to use the Excavation Calculator
- Choose the shape: rectangular pit, trench or round hole, and how many.
- Enter the bottom dimensions and depth, and a side slope if the walls are sloped back.
- Pick the soil type or enter your own swell, shrinkage and weight.
- Set the truck size and payload; add a cost per load for the haul estimate.
- Read the loose cubic yards and loads, and compare other soils in the table.
Excavation formulas
- Rectangular pit, vertical sides: V = L × W × D
- Rectangular pit, sloped sides (slope s : 1): top = (L + 2sD) × (W + 2sD); V = D ÷ 6 × (Abottom + 4 Amiddle + Atop)
- Trench with sloped sides: V = L × D × (W + sD), a trapezoid cross-section with vertical ends
- Round hole: V = π r² D, or with sloped sides V = πD ÷ 3 × (r₁² + r₁r₂ + r₂²)
Then: BCY = cu ft ÷ 27; LCY = BCY × (1 + swell); CCY = BCY × (1 − shrinkage); loads = the larger of LCY ÷ truck capacity and tons ÷ payload, rounded up.
Example: a 30 × 40 ft basement 8 ft deep with vertical walls is 9,600 cu ft = 355.6 BCY. In common earth with 25% swell that is 444.4 LCY, about 498 tons, so 45 loads in a 10 cu yd truck (volume limits before the 13-ton payload).
Typical soil swell, shrinkage and weight
Rounded figures used by the calculator. Actual values vary with moisture, compaction and grading.
| Material | Swell | Shrinkage (compacted) | Bank weight (lb/cu yd) | Loose cu yd per bank cu yd |
|---|---|---|---|---|
| Sand | ~12% | ~10% | ~2,900 | 1.12 |
| Gravel | ~15% | ~7% | ~3,100 | 1.15 |
| Topsoil / loam | ~30% | ~15% | ~2,300 | 1.30 |
| Common earth | ~25% | ~10% | ~2,800 | 1.25 |
| Clay | ~35% | ~10% | ~3,000 | 1.35 |
| Broken rock | ~60% | bulks ~30% | ~4,200 | 1.60 |
Planning tips
- Call 811 before you dig (in the US) so gas, power, water and communication lines are marked.
- Keep spoil back from the edge. Piles of excavated soil should sit at least 2 ft from the edge of a trench so they don't fall back in or overload the wall.
- Plan for over-dig. Basements and foundations are dug a couple of feet wider than the footprint to give working room, so include that in the length and width.
- Reuse what you can. Backfill and grading can use some of the spoil, cutting truck loads; the compacted volume tells you how much space it will fill.
- Ask how the hauler charges: per load, per hour or per ton, and whether a dump fee is extra.
Frequently asked questions
What is the difference between bank and loose cubic yards?
Bank cubic yards (BCY) measure soil in place in the ground. Once dug, soil breaks up and takes more space; that is loose cubic yards (LCY). Loose volume = bank volume × (1 + swell). Trucks are loaded by loose volume, so a 100 BCY dig in common earth with 25% swell fills about 125 cubic yards of truck space.
What is the swell factor of soil?
Swell is the percentage increase in volume when soil is excavated. Typical values are about 10–15% for sand and gravel, 20–30% for common earth and loam, 30–40% for clay and 50–70% for blasted or broken rock. Moisture and how the soil is dug change the figure, so use local data when you have it.
How do I calculate excavation volume?
For a box-shaped hole, multiply length × width × depth in feet and divide by 27 for cubic yards. With sloped sides, use the prismoidal formula V = D ÷ 6 × (bottom area + 4 × middle area + top area). For a round hole, V = π × r² × depth. Then apply the swell factor to get the loose volume to haul.
How many cubic yards fit in a dump truck?
A small single-axle dump truck holds about 5–7 cubic yards, a tandem-axle truck about 10–14 and a tri-axle or semi dump 16 yards or more. With heavy wet clay or rock the truck often reaches its legal weight limit before the box is full, which is why the calculator checks both volume and weight.
How much does a cubic yard of dirt weigh?
In place, common earth weighs roughly 2,500–3,000 lb per cubic yard (about 1.25–1.5 tons), clay about 3,000 lb, and sand and gravel 2,900–3,200 lb. Wet soil can weigh noticeably more. Loose soil weighs less per cubic yard because the same mass takes up more space.
What is shrinkage in earthwork?
Shrinkage is the opposite of swell: when excavated soil is placed and compacted as fill, it usually ends up about 5–20% smaller than its bank volume. Broken rock is the exception; it stays bulkier than its original in-place volume even when compacted.
Do I need to slope or shore an excavation?
Under US OSHA rules, trenches 5 ft deep or more generally need a protective system such as sloping, benching, shoring or a trench box unless they are entirely in stable rock. Allowed slopes depend on soil type: ¾:1 for Type A, 1:1 for Type B and 1½:1 for Type C. A competent person must assess the site.
Are all the tools on FreeToolCabin tested for quality and accuracy?
Yes! Every tool on our site undergoes automated Q/A testing in real browser environments to ensure high precision, correct output, and zero errors. If you happen to spot a bug or have a suggestion, please contact us at [email protected] and our team will review it right away.