Excavation Volume and Truck Load Calculator
How much spoil is coming out of the hole, and how many truck loads will it take to haul it away. Enter the dig dimensions, pick a soil type with the right swell factor, and see bank volume, loose volume, and truckloads in real time. Built for excavation contractors, not landscapers or DIYers buying mulch.
The math, shown transparently
No black box. Here is exactly what the calculator computes on every input change. If any of these numbers look wrong, cross-check with a calculator of your own.
// Bank volume. In-place, undisturbed.
bank_ft³ = length × width × depth (imperial)
bank_yd³ = bank_ft³ / 27
bank_m³ = length × width × depth (metric)
bank_yd³ = bank_m³ / 0.9144³ (NIST yd to m)
// Loose volume. After the dirt comes out and bulks up.
loose_yd³ = bank_yd³ × swell_factor
// Truck loads. Always rounds up. A partial load is still a trip.
loads = ceil(loose_yd³ / truck_capacity_yd³)
Worked example
A 10 ft × 10 ft × 10 ft hole in common earth, hauled with a standard 12 yd³ tandem dump:
bank_ft³ = 10 × 10 × 10 = 1000 ft³
bank_yd³ = 1000 / 27 = 37.04 yd³
swell = 3,200 / 2,550 = 1.2549 (Cat, earth dry packed)
loose_yd³ = 37.04 × 1.2549 = 46.48 yd³
loads = ceil(46.48 / 12) = ceil(3.873) = 4 loads
You can verify this and every other example in the test suite with any cubic yard calculator. The math is pure, no server calls, and the numbers are locked in a unit test so they cannot drift.
How swell factors work
When you excavate dirt, rock, or sand, it occupies more space loose than it did in the ground because it picks up air gaps. A swell factor (sometimes called a bulking factor) is the multiplier between in-place bank volume and loose excavated volume.
Swell = bank weight ÷ loose weight for the same material. A cubic yard of common earth weighs 3,200 lb in the bank and 2,550 lb loose in Caterpillar’s table, so it takes up 1.25 yd³ in the truck. The value for every soil is listed under Sources and assumptions below. Real-world values vary with moisture and how the loader works the material, so treat them as planning numbers, not surveyed measurements.
Sources and assumptions
- Swell is Caterpillar’s bank weight divided by its loose weight for the same material, from Material Density Tables to Help Estimate Earthwork Volumes (archived copy): common earth (dry packed) 25%, loam 24%, topsoil 44%, sand (dry) 13%, sand (wet) 13%, gravel (dry) 12%, gravel (wet) 12%, clay (dry) 24%, clay (wet) 25%. Cat notes weight varies with moisture, grain size, and compaction.
- Blasted rock and mixed debris are not presets: pick Other material and enter the swell from your own numbers.
- 10-wheeler (tandem dump) 12 yd³. TxDOT: usually 12 or 14 yd³. Uses 12. Source: TxDOT Seal Coat and Surface Treatment Manual, Haul Trucks.
- Tri-axle dump 16 yd³. Load King: 16 to 19 yd³ for a 16 to 18 ft body. Uses 16, the low end. Source: Load King tri-axle dump body specs (Custom Truck One Source).
- Other trucks have no default; enter your bed size. For reference: belly dump 22 yd³ (Trail King bottom dump specs); belly dump 27 yd³ on a 40 ft tandem-axle trailer (MAC Bullet bottom dump flyer); semi end dump 29.0 yd³ with a 32 ft tub (Load King RH3229 end dump specs (archived)).
How to use the calculator
- Pick your units. Imperial (feet and cubic yards) or metric (meters and cubic meters). Your choice is saved for next time.
- Enter the dig dimensions. Length, width, and depth. For irregular shapes, break the hole into rectangles and add them up.
- Select a soil type. Pick the closest match. If the site has a mix of materials, run the calculator once per soil and add the loads.
- Pick your truck. Choose from standard dump truck capacities or enter a custom value in cubic yards.
- Read the numbers. Bank volume, loose volume, and truckloads update in real time. Loose volume is what actually hits the truck bed.
Frequently asked questions
What is the difference between bank volume and loose volume?
Bank volume is the in-place, undisturbed dirt. It is what you measure from the plans before you dig. Loose volume is what you haul away after the dirt has been dug and bulked up with air. Loose is always bigger than bank. The multiplier between them is the swell factor, and it depends on the soil. From Caterpillar’s loose and bank weights, dry sand swells about 13%, wet clay about 25%, and topsoil about 44%.
Why does my cubic yard calculator say I need more loads than yours?
Many cubic yard calculators skip swell and count 1 yd³ in the ground as 1 yd³ in the truck. Dig 100 yd³ of common earth and you haul about 125 yd³ loose. For the soils here, loose runs 12% to 44% bigger than bank, so counting loads on bank volume comes up short.
Where do your swell factors come from?
Each one is Caterpillar’s bank weight divided by its loose weight for the same material, from Cat’s published loose and bank table. The dump truck load calculator uses the same table, so the two tools agree. Blasted rock and mixed debris are not presets because we found no published loose and bank weights for them: pick Other material and enter your own swell.
Why does a partial load count as a full truckload?
Because you can't send half a truck. A 12 yd³ truck carrying 0.5 yd³ of spoil is still one trip to the dump. Same fuel, same driver time, same tipping fee. The calculator always rounds up, matching how real trucking billing works.
Does the calculator account for truck weight limits?
No. Truck capacities here are volumetric (cubic yards). A full bed of heavy material can weigh more than the truck may legally carry, and how much less you can haul depends on your truck’s legal payload. The dump truck load calculator works that out: pick the material and truck, enter your payload, and it tells you whether weight or volume runs out first.
Is this free forever?
Yes. No signup, no email, no watermark. SpoilStack is a paid job tracker for excavation contractors. This tool is free.
Related free tools
- Equipment Hourly Rate Calculator. What to charge per hour for your excavator.
- Job Cost Estimator. Build a full bid from equipment, trucking, labor, and materials.
- Haul Ticket Generator. Print dump truck load tickets for the job.