# Excavation Calculator

> Calculate excavation step by step: V = D ÷ 6 × (A_bottom + 4·A_mid + A_top) (prismoidal formula).

Page: https://freecalculator.tech/tools/excavation-calculator
Last reviewed: 2026-11-03

## Formula

V = D ÷ 6 × (A_bottom + 4·A_mid + A_top) (prismoidal formula). Loose = bank × (1 + swell).

- Slope 0 gives vertical sides (a simple box).
- Prismoidal formula is exact for a pit with uniform side slopes.
- Swell factor is entered from soil data; no soil type is assumed.
- V = D ÷ 6 × (A_bottom + 4·A_mid + A_top) (prismoidal formula). Loose = bank × (1 + swell).
- Inputs used: Base length, Base width, Depth, Side slope (horizontal per 1 vertical), Swell factor.

## Inputs

- Base length
- Base width
- Depth
- Side slope (horizontal per 1 vertical)
- Swell factor

## Worked example: 10 × 5 m pit, 2 m deep, 1:1 slopes

Swell 25%.
1. Top = 14 × 9 = 126 m²; bottom = 50 m²; mid = 12 × 7 = 84 m².
2. V = 2/6 × (50 + 336 + 126) = 170.7 m³.
3. Loose = 170.7 × 1.25 = 213.3 m³.

## Common questions

### What is swell?

Soil bulks up when dug. Trucks carry loose volume, so haulage is based on bank volume increased by the swell factor.

### What side slope is safe?

It depends on soil and local safety rules for trenching and excavation. A competent person must decide; this tool only computes volume.

### Is the pit assumed level?

Yes, with a flat bottom and level ground.

### How do I use the Excavation Calculator?

Enter the required values for Base length, Base width, Depth, Side slope (horizontal per 1 vertical), Swell factor. The calculator applies the formula on this page and shows the main result with any supporting breakdown so you can check the arithmetic.

### What formula does the Excavation Calculator use?

V = D ÷ 6 × (A_bottom + 4·A_mid + A_top) (prismoidal formula). Loose = bank × (1 + swell). The visible formula section above lists the calculation path and the edge cases the page handles, so the result can be checked without relying on the form alone.

### Can the Excavation Calculator be used for exact decisions?

Use it as a calculation aid, not as a substitute for checking the underlying rule, contract, policy, or professional advice that applies to your situation. When a result depends on local rules, personal details, prices, or dates, enter those values yourself and confirm them before acting.

## Limitations and assumptions

- Level ground, flat bottom, uniform slopes.
- Swell is user-entered.
- Does not assess excavation safety.
- Results are estimates for planning and learning. Real designs, installations and bids must be checked by a qualified, licensed professional against the codes that apply where you work.
- The result depends on the values you enter for this excavation calculator; it does not supply missing rates, rules, prices, dates, or assumptions for you.

## Sources

- OpenStax (Rice University) — https://openstax.org/details/books/calculus-volume-2

## Cite this page

- APA: Free Calculator. (2026, November 3). Excavation Calculator. https://freecalculator.tech/tools/excavation-calculator
- MLA: "Excavation Calculator." Free Calculator, 3 Nov. 2026, https://freecalculator.tech/tools/excavation-calculator.
- Link: Excavation Calculator — Free Calculator, https://freecalculator.tech/tools/excavation-calculator