Concrete Weight Calculator: How Much Does Concrete Really Weigh?

Concrete is shockingly heavy — and underestimating that weight is how trailers get overloaded, forms blow out, and backs get injured. Here's exactly how much concrete weighs in every unit you'll actually use.

The numbers that matter

| Unit | Weight (approx.) | |---|---| | 1 cubic foot | 145–150 lbs | | 1 cubic yard (27 cu ft) | ~4,000 lbs (2 tons) | | 1 gallon (wet) | ~12.5 lbs | | 60-lb bag (dry mix) | 60 lbs | | 80-lb bag (dry mix) | 80 lbs |

The standard figure engineers use: normal-weight concrete = 150 pounds per cubic foot. Lightweight mixes run 90–120 pcf; heavyweight mixes (radiation shielding, counterweights) go 180+ pcf.

Plain vs. reinforced

Steel rebar adds surprisingly little to the total:

• Plain concrete: ~145 pcf
• Reinforced concrete: ~150 pcf

A typical slab with rebar on 12-inch centers is only about 3–4% heavier than plain concrete. For weight estimates on any normal project, just use 150 pcf and you'll be within a few percent.

Weight per bag (and what each bag pours)

Bagged concrete mix is sold by dry weight, but what you care about is coverage:

| Bag size | Dry weight | Wet volume (yield) | |---|---|---| | 40-lb bag | 40 lbs | ~0.30 cu ft | | 60-lb bag | 60 lbs | ~0.45 cu ft | | 80-lb bag | 80 lbs | ~0.60 cu ft |

Rule of thumb: an 80-lb bag makes about 0.6 cubic feet. So a 4-inch-thick 10×10 ft slab (33 cu ft) needs roughly 56 bags of 80-lb mix — that's 4,480 lbs of bags to haul, lift, and mix. This is the moment most DIYers switch to a ready-mix truck.

Why weight matters: trailers and trucks

This is where the math gets practical — and where people get in trouble:

• A cubic yard of concrete (4,000 lbs) exceeds the payload of most half-ton pickups (typically 1,500–2,000 lbs payload). Hauling even half a yard in a pickup is pushing it.
• A standard single-axle utility trailer (3,500-lb GVWR) can legally carry roughly one cubic yard at most — and that's before the trailer's own weight.
• Ready-mix trucks carry 8–10 cubic yards: 32,000–40,000 lbs of concrete. That's why they need reinforced drums and why you never want one on a soft driveway without plywood down.

Check your vehicle's payload sticker (driver's door jamb) before hauling bagged mix. Fifty 80-lb bags = 4,000 lbs — two tons riding on your suspension and brakes.

Forms have to hold it too

Wet concrete behaves like a liquid — it pushes sideways, not just down. Formwork pressure at the bottom of a 4-foot wall pour can exceed 600 lbs per square foot of form face. That's why:

• Stakes every 2–3 feet on slab edge forms (not every 6)
• Wall forms need ties or whalers rated for the pour height
• Never reuse visibly bowed or cracked form lumber for a structural pour

A blown-out form doesn't just waste concrete — 4,000 lbs of wet mix spreading across your yard is a cleanup nightmare.

Quick weight formula

Weight (lbs) ≈ volume (cu ft) × 150

Examples:

• 4″ × 10′ × 10′ slab = 33.3 cu ft → ~5,000 lbs
• Sonotube footing, 12″ diameter × 4′ deep = 3.1 cu ft → ~470 lbs
• Standard 4′ × 8″ × 16″ concrete block ≈ 0.3 cu ft → ~45 lbs (that's why they're rated by hand!)

Planning the pour itself? Our free concrete calculator figures out exactly how many yards or bags your project needs — so you can size the truck, the trailer, and your crew before the concrete shows up.