Concrete Calculator
Free concrete calculator. Instant cubic yards plus 40, 60, 80 lb bag counts for slabs, footings, and post holes. Last reviewed August 2026. No sign-up, no email.
How much does a cubic yard of concrete weigh?
One cubic yard of concrete weighs 4,050 lb (2.03 US tons).
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One cubic yard of concrete = 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags.
One cubic yard of concrete is 0.8 half-ton pickup loads, or about 0.06 tandem-axle dump truck loads.
Concrete is the most-used material after water on the planet, and the most-asked-about in the cubic yard calculator. A cubic yard of concrete weighs about 4,050 lb (2.025 US tons) cured. One cubic yard fills a 10×10 ft slab at 3 inches deep, a 10×10 ft slab at 3.24 inches deep to be exact.
For slabs 4 inches thick, 1 yd³ covers 81 ft². For 6-inch driveways, 1 yd³ covers 54 ft². The calculator defaults to a 4-inch patio / walk depth because that's the most common residential use.
Ready-mix vs bagged concrete
- Ready-mix concrete is delivered by a concrete truck (typically 8–10 yd³ per load) and is the right answer for any pour over 1 yd³. Per yard delivered, it's $150–$200 in most US markets; pour 1 yd³ or more and bagged concrete makes no economic sense.
- Bagged concrete (80 lb / 60 lb / 40 lb bags) is the right answer for small jobs — fence post holes, sonotubes, a small walk, a mailbox post. One yd³ = 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags. Use the concrete bag calculator for those.
How much concrete for a 20×20 slab?
A 20×20 ft garage slab at 6 inches: 400 × 6 ÷ 12 ÷ 27 = 7.4 yd³. Order 8 yd³ (10% waste) and have the truck back right up to the forms — wheelbarrowing 8 yards of concrete is back-breaking work.
Waste and overage
The calculator defaults to 10% waste, which covers:
- Spillage during the pour
- Over-excavation (the bottom of the hole isn't perfectly flat)
- Short loads (a yard short at the end of a pour is a disaster)
For a difficult site (narrow access, lots of rebar, lots of corners), bump waste to 15%.
Concrete strength
Residential concrete is usually 3,000 to 4,000 psi at 28 days. The calculator assumes a generic "concrete" density; for high-strength or lightweight concrete, the weight per yard changes. For 99% of homeowner projects, 4,000 psi ready-mix is the right choice.
Frequently asked questions
How much does a yard of concrete weigh?
One cubic yard of concrete weighs about 4,050 lb (2.025 US tons) cured. Wet, it's closer to 3,900 lb.
How many bags of concrete are in a yard?
One cubic yard of concrete equals 45 × 80 lb bags, 60 × 60 lb bags, or 90 × 40 lb bags.
How thick should a concrete slab be?
4 inches is the residential default for patios and walks; 6 inches for driveways and garage floors.