Yards
Concrete Yard Calculator
Ready-mix is ordered in cubic yards. The big number is the exact volume with your extra. The plant line rounds up to the next 0.25 yard.
Your region
Feet, inches, cubic yards, and 40–80 lb bags
Concrete Calculator
Example measurements — replace them with yours.
Common sizes
Most orders add 5–10% for spillage, uneven ground, and the last bit left in the chute.
Cost, truck size, and concrete weight
Leave a price blank to skip that estimate. Use the number your supplier quoted.
This job
Add each pour — slab, piers, steps — and Concrete Calculator totals them.
Quick answer
Concrete Yard Calculator: cubic yards = (length × width × thickness in feet) ÷ 27. Add 5–10% waste, then round up to the next 0.25 yard for most ready-mix plants. Under about 0.75 yards, bags are usually simpler — switch to the bag calculator on the same volume.
How a concrete yard calculator should behave
Show the exact volume and the order volume separately. Exact math helps you check. The plant sells quarter yards. Concrete Calculator prints both, plus ft³ and m³ so metric tickets still make sense.
Coverage shortcuts: 81 ft² per yard at 4 inches, 54 ft² at 6 inches, 40.5 ft² at 8 inches. Divide area by coverage for a fast takeoff, then confirm with dimensions. The guide what is a yard of concrete? unpacks coverage, weight, and bags for one yard.
| Thickness | Coverage per yd³ |
|---|---|
| 4 in | 81 ft² |
| 5 in | 64.8 ft² |
| 6 in | 54 ft² |
| 8 in | 40.5 ft² |
Worked example with the concrete yard calculator
Add every rectangle in the job first. Rounding each pier to a quarter yard on its own over-orders — a classic takeoff mistake when six sonotubes each “need 0.25 yd.”
- 12×12×4 in → 1.78 yd³ neat → 2.00 ordered at 10% waste
- 20×24×6 in → 8.89 yd³ neat → 10.00 ordered at 10%
- Known 2.10 yd³ + 5% → 2.205 → order 2.25
Tips before you call the plant
Ask about short-load fees under about 3–4 yards. Enter truck size if your plant sends 8-yard mixers instead of 10. Strength (psi / MPa) is a mix ticket item — volume still comes from this page. Read how to calculate yards if you want the inch conversion spelled out slowly.
How many yards of concrete do I need — worked pads
A 10×10×4 in pad is 1.23 yd³ neat. A 12×12×4 in pad is 1.78 yd³. A two-car 24×24 garage slab at 4 inches is 7.11 yd³ neat; at 6 inches it is 10.67 yd³. Driveways jump again: 20×40 at 6 inches is 14.8 yd³ neat before waste. Write the neat number, add waste, then round — in that order.
When someone asks for a concrete yardage calculator, they usually need quarter-yard rounding more than a new formula. Plants do not sell 1.37 yd³. They sell 1.50. Concrete Calculator prints both so you can show the dispatcher the exact math and the order quantity.
Multi-pour jobs and short loads
Garage slab + four sonotube piers + a stoop is one plant call if you add the pours first. It is three confusing tickets if you round each shape alone. Short-load fees under about three or four yards can erase the savings of “just ordering a little.” Compare bags on the same volume when the fee shows up.
Truck size matters for load counts on big pours. An 8 yd mixer and a 10 yd mixer change how many trips a 22 yd order needs. Set truck size on the ready-mix calculator after this page gives you the order yards.
Related tools
Bag calculator for bag conversions · Ready-mix for load counts · Weight for tons.
Frequently asked questions
How many yards of concrete do I need?
L×W×T in feet ÷ 27, plus waste, then round to 0.25 yd for the truck.
What is a yard of concrete in square feet?
81 ft² at 4 in, 54 at 6 in, 40.5 at 8 in.
How many cubic feet in a yard?
27.
Why quarter yards?
Plants batch in 0.25 yd steps more often than hundredths.
How many bags in a yard?
45×80 lb, 60×60 lb, or 90×40 lb at standard yields.