Digging a trench, footing, or basement and need to know how much material is coming out of the ground? This excavation calculator works out the volume from your length, width, depth, and side slope, then converts it into loose (swelled) volume so you know how much material actually needs hauling away, plus how many truck loads that means.

Pick a type to load sensible starting dimensions, or switch to custom and enter your own.

Why people use this tool

• Accounts for sloped sides: trenches and pits with battered walls are wider at the top than the bottom, and this calculator handles that tapered shape automatically instead of treating it as a simple box.
• Converts bank volume to loose volume: soil expands once it’s dug up, so the swell factor tells you how much extra volume you’ll actually be hauling away.
• Estimates truck loads: enter your truck’s capacity and get a straight count of loads needed for disposal.
• Optional cost breakdown: add your excavation and disposal rates to get a total estimate, broken down by line item.

How excavation volume is calculated

The calculator treats the hole as a frustum, a shape that widens or narrows with depth. Given a bottom length and width, a depth, and a side slope ratio, it works out the top dimensions and applies the standard frustum volume formula, averaging the bottom, top, and mid-height cross-sections.

A vertical-sided trench (a 0:1 slope) has the same width at top and bottom, so the math reduces to length times width times depth. A trench with sloped sides ends up noticeably larger than that simple calculation, which is why the slope setting matters once you’re digging deeper than a shallow trench.

For example, a trench measuring 10m long, 0.6m wide, and 1m deep with vertical sides works out to a 6m³ bank volume. The same trench in imperial, roughly 33ft long, 2ft wide, and 3ft deep, comes out to about 7.85yd³.

Bank volume vs loose volume

Bank volume is the volume of soil while it’s still in the ground, undisturbed. Once you dig it up, it loosens and takes up more space, typically 12% to 60% more depending on soil type. Sand and gravel swell the least, clay swells more, and blasted rock can nearly double in volume.

This calculator lets you pick a soil type preset or enter a custom swell percentage, and reports bank and loose volume separately so you’re not caught short when the loose pile turns out bigger than the hole it came from, or when ordering trucks sized for the wrong figure.

In common earth (25% swell), that same 6m³ trench becomes 7.5m³ once it’s dug. In imperial, 7.85yd³ bank volume becomes about 9.8yd³ loose.

Estimating truck loads and cost

Enter your truck’s capacity and the calculator divides your loose volume by it, rounding up, since a partial load still needs a full trip. Toggle on cost estimation and enter your excavation price (per bank volume) and disposal price (per loose volume) to get a line-by-line cost breakdown plus a total, so you can see how much of the budget is digging versus hauling material away.

If you’re pouring concrete into the hole once it’s dug, the Concrete Calculator works out cement, sand, and aggregate for the pour. For a wall going up nearby, try the Brick Calculator. For unit conversions, the Volume Converter and Weight Converter can help with a supplier or hauler quote.

These figures are for planning purposes. Trenches and pits carry real collapse risk once they get deep, so confirm shoring, sloping, and safety requirements with a licensed contractor or engineer before digging.