How many yards fit in a dump truck? Less than the box says
Ask how many yards a dump truck holds and you will get an answer about the box. Ask a driver hauling stone and you will get a different answer, because on heavy material the scale house decides the load, not the sideboards.
Here are the numbers that actually matter when you are figuring loads for a job.
Box volume by truck type
Struck capacity, meaning level with the sides, no crown:
- Single-axle dump: 5 to 6 cubic yards
- Tandem (10-wheeler): 10 to 14 cubic yards
- Tri-axle: 15 to 17 cubic yards
- Quad and quint axle: 17 to 22 cubic yards
- Super dump / trailing axle: up to 26 cubic yards
- End dump trailer: 20 to 26 cubic yards
A heaped load carries a little more than struck, but heaping stone over the sides is how material ends up on someone's windshield, so plan around struck numbers.
Why the box lies on heavy material
Legal gross weight caps the load long before the box fills on dense material. A tri-axle typically hauls 15 to 18 tons of payload legally, depending on state axle rules. Now do the math on what a yard weighs:
- Mulch runs about 400 to 800 pounds a yard. The box fills first. All 17 yards ride.
- Topsoil runs about a ton a yard. The box and the scale hit their limits together.
- Crushed stone runs about 1.4 tons a yard. Sixteen tons of payload is only 11 to 12 yards, in a box that could physically hold 17.
That is why a supplier quotes you "a tri-axle load" of stone as 12 yards while the mulch yard calls the same truck 17. Neither one is wrong. Wet material makes it worse: damp sand picks up a few hundred pounds a yard, and a load that scaled legal in a dry week can be overweight after rain.
Figuring loads for a job
The working method, whatever you drive:
- Get the volume: length by width in feet, times depth in inches divided by 12, gives cubic feet. Divide by 27 for yards.
- Check the weight: multiply yards by the material's pounds per yard and compare against what your truck legally hauls.
- Loads are the volume divided by whichever number is smaller, box yards or weight-limited yards, rounded up.
Our free dirt calculator does all three steps: enter the dimensions, pick the material, put in your own truck's capacity in yards, and it gives yards, tons, and loads. There are matching calculators for gravel, sand, and asphalt tonnage.
One more thing on swell
Excavated material is bigger than the hole it came out of. Bank dirt swells 20 to 30 percent when dug, so a 100-yard basement dig is 120 to 130 loose yards on trucks. If you quote trucking off the hole dimensions, you eat the difference. Figure loads on loose yards going out and compacted yards coming in.
We built TrackOver inside a working excavation company, and load math like this is exactly the kind of thing we wanted answered in the truck, not back at the office. The calculators are free either way.
Common questions
How many yards fit in a dump truck? Struck capacity, meaning level with the sides: a single-axle holds 5 to 6 cubic yards, a tandem 10 to 14, a tri-axle 15 to 17, quad and quint 17 to 22, a super dump up to 26, and an end dump trailer 20 to 26. Plan around struck numbers rather than heaped ones, because heaping stone over the sides is how material ends up on somebody's windshield.
Why does a supplier say 12 yards of stone but 17 yards of mulch in the same truck? Because legal weight caps the load long before the box fills on dense material. A tri-axle hauls roughly 15 to 18 tons legally. Mulch runs 400 to 800 pounds a yard so the box fills first and all 17 yards ride. Crushed stone runs about 1.4 tons a yard, so 16 tons of payload is only 11 or 12 yards in a box that could physically hold 17. Neither number is wrong.
How much does a yard of material weigh? Roughly: mulch 400 to 800 pounds, topsoil about a ton, crushed stone about 1.4 tons. Those are the figures that decide whether the box or the scale limits your load, and wet material makes all of them heavier.