What concrete weighs
| Type | lb/ft³ | Per cubic yard |
|---|---|---|
| Normal-weight concrete | 140–150 | 3,780–4,050 lb |
| Structural lightweight concrete | 90–120 | 2,430–3,240 lb |
Ranges from NRMCA. Almost all residential concrete — bagged or ready-mix — is normal-weight.
The formula
The calculator uses the middle of the range — 145 lb/ft³ for normal-weight concrete — and shows the low and high ends so you can plan for the heavier case.
Breaking out old concrete
Broken concrete weighs exactly what it did in place but takes up more room, because the pieces don’t pack tightly. Dumpsters and trailers are limited by weight long before they’re full of concrete — a 10 × 10 ft, 4 in slab weighs about 4,800 lb. Check the weight limit, not just the size, before you rent.
Questions people ask
How much does a cubic yard of concrete weigh?
About 2 tons. Normal-weight concrete is 140–150 lb per cubic foot, so a 27 ft³ yard weighs 3,780–4,050 lb.
How much does a 4 in slab weigh per square foot?
Roughly 47–50 lb. A square foot of 4 in slab is a third of a cubic foot.
Is wet concrete heavier than dry?
Fresh concrete includes all its mixing water. In NRMCA’s worked example a fresh mix weighs 151 lb/ft³, just above the 140–150 lb/ft³ range for hardened concrete.
What does a bag of concrete weigh once it’s mixed and set?
Roughly what it says on the bag plus some of the water you add. Quikrete puts the density of its standard Concrete Mix at about 140 lb/ft³, so an 80 lb bag’s 0.60 ft³ sets at around 84 lb.
Sources for the numbers on this page
- National Ready Mixed Concrete Association — CIP 36 — Structural lightweight concrete (unit weights) · checked October 1, 2026
- National Ready Mixed Concrete Association — CIP 8 — Discrepancies in yield (ordering 4–10% extra) · checked October 1, 2026
- Quikrete — Concrete Mix No. 1101 — technical data sheet (bag yields, strength gain, curing) · checked October 1, 2026
Corrections and updates are logged on the sources page.