# Excavation Earthwork Calculator

> Calculate excavation volume for a pit or trench with vertical or sloped sides, the loose volume after swell and the number of truckloads to haul it away.

Category: Construction · Applies to: Worldwide · Last updated: 2026-10-29
Interactive calculator: https://calculators.geekmidst.com/calculators/excavation-earthwork-calculator

Soil in the ground (bank volume) bulks up once dug (loose volume). Sloped sides make the hole wider at the top, so the volume uses the prismoidal formula.

Also called: Dig volume calculator, Earthworks calculator.

## Inputs
- Units (options: Metric, Imperial; default metric)
- Bottom length (default 10)
- Bottom width (default 5)
- Depth (default 2)
- Side slope (horizontal per 1 vertical) (unit : 1; default 0.5; optional)
- Number of identical pits (default 1; optional)
- Swell factor (unit %; default 25; optional)
- Truck capacity (loose) (default 10)

## Results
- Bank (in-place) volume
- Bank volume
- Loose volume to haul
- Loose volume to haul
- Truckloads
- Area at the top of one pit

## Formula

```
V = D ÷ 6 × (A_bottom + 4 A_middle + A_top);  A at depth z uses (L + 2s·z)(W + 2s·z);  Loose = V × (1 + Swell)
```

Where:
- L, W: bottom length and width
- D: depth
- s: side slope, horizontal per 1 vertical

## Worked example
1. Bottom 10 × 5 = 50 m²; top (10 + 2) × (5 + 2) = 84 m²; middle 11 × 6 = 66 m².
2. V = 2 ÷ 6 × (50 + 4 × 66 + 84) = 132.667 m³.
3. Loose = 132.667 × 1.25 = 165.833 m³ ÷ 10 m³ = 16.6 → 17 truckloads.

**Result:** A 10 × 5 m pit 2 m deep with 0.5:1 sides holds 132.7 m³ in the ground, about 166 m³ loose, or 17 ten-cubic-metre loads.

## What the result means

Price digging on the bank volume and haulage on the loose volume. If the soil goes back as compacted fill, it shrinks below its bank volume.

## Assumptions and limits
- Level ground and a flat, rectangular bottom.
- All four sides have the same slope.
- Swell factors vary widely with soil and moisture; a site investigation gives better values.
- Does not assess trench stability or shoring.

## Questions

### What is the difference between bank and loose volume?

Bank volume is soil as it sits in the ground; once dug it loosens and takes up more space, by the swell percentage.

### Is the prismoidal formula exact here?

Yes. For a pit with straight, evenly sloped sides the cross-section area is a quadratic in depth, which the prismoidal formula integrates exactly.

## Related calculators
- [Site Cut and Fill Volume Calculator](https://calculators.geekmidst.com/calculators/site-cut-and-fill-volume-calculator)
- [Foundation Concrete Calculator](https://calculators.geekmidst.com/calculators/foundation-concrete-calculator)
- [Pile Concrete Volume Calculator](https://calculators.geekmidst.com/calculators/pile-concrete-volume-calculator)

_Quantities are estimates. Confirm requirements with your engineer or supplier before ordering materials._

Source: GM¹X CalcVerse — https://calculators.geekmidst.com/calculators/excavation-earthwork-calculator