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PlanQty

Trench Spoils Calculator

Estimate loose cubic yards and truck counts from bank excavation. Swell accounts for the volume increase when soil is dug and loaded.

In-place excavation, before swell

%

Typical: sand 10–15%, clay 20–30%, rock 30–50%

Loose cubic yards per load

Enter your values, then press Calculate.

How to calculate

Enter bank cubic yards from the trench excavation calculator, or any known bank volume. Choose a swell factor for the material and the truck capacity you are using.

Formula

Loose CY = bank CY × (1 + swell). Truckloads = ceil(loose CY ÷ truck capacity). Pipe displacement can be subtracted when the pipe stays in the trench.

Common use cases

  • Haul-off estimates
  • Comparing 10 CY vs 16 CY trucks
  • Checking if spoils stay on site
  • Utility trench waste haul

Assumptions

  • Bank volume is already known from the trench excavation (or another neat-line) calculator.
  • Swell percent is the increase from bank to loose, from a geotech note or past loads — not a soil name.
  • Truck capacity is heaped loose yards, the same unit as the swollen volume.
  • If truck count is used, loads round up to whole trucks.

Limitations

  • Does not compute the trench prism. Start on trench excavation if you only have length, width, and depth.
  • Does not guess clay versus sand. Type the swell you were given.
  • Does not shrink the material back to compacted fill; that is the shrink/swell tool.
  • Does not price haul or dump fees.

Worked examples

30 bank CY at 25% swell in 12 CY trucks

30 bank yd³ × 1.25 = 37.5 loose yd³. 37.5 ÷ 12 = 3.125, which rounds to 4 trucks. That extra truck is why swell belongs before the load count.

  1. 1. Loose volume after swell

    30 yd³ × (1 + 25%) = 37.5 yd³

  2. 2. Truckloads

    ceil(37.5 ÷ 12) = 4 loads

Cubic feet bank volume

  1. 1. Loose volume after swell

    30 yd³ × (1 + 0%) = 30 yd³

  2. 2. Truckloads

    ceil(30 ÷ 10) = 3 loads

After the bank cut, before the trucks

Start with bank yards from the trench excavation calculator (or a neat-line pay quantity). Swell turns that in-place volume into loose yards: loose = bank × (1 + swell/100). Truckloads divide loose yards by the capacity you actually get. This page does not compute the trench prism itself and does not apply shrink for compacted fill.

Swell is not a soil name

Sand and gravel often swell 10–15%, clay 20–30%, blasted rock 30–50%. Those ranges are reminders, not defaults invented from a dropdown. Use the geotech report or past loads from the same cut. High swell (the 60% warning example) is a prompt to confirm the factor, not a recommendation.

A 25 percent swell is not a soil classification

Thirty bank yards at 25% swell is 37.5 loose yards. In 12-yd trucks that is 4 loads, because 37.5 ÷ 12 = 3.125 and you cannot send 0.125 of a truck. Native clay on one job may swell 20%; shot rock on the next may swell 40%. The calculator will not look up a soil. If the inspector pays bank yards and the hauler bills loose loads, keep both numbers — this page is the loose side.

Related calculators

FAQ

What swell factor should I use?

Sand and gravel are often 10–15%, clay 20–30%, and blasted rock 30–50%. Confirm with the geotech report or past loads from the same cut.

Are truckloads heaped or struck?

Enter the capacity you actually get, usually less than the nameplate if the material is wet or the tailgate leaks.

Why is my truck count higher than bank yards ÷ capacity?

Because swell increases the volume before you divide by truck size, and the last load rounds up. Bank yards in a 12-yd truck without swell under-counts the haul.

Can I enter cubic feet of bank?

Yes. The volume unit converts to cubic yards first, then swell is applied.

Disclaimer

These calculators are estimating tools for planning and field checks. They are not a substitute for approved plans, specifications, licensed professional engineering, or governing standards. Confirm densities, waste factors, and yields with your supplier and project documents.