Concrete Weight Calculator
Need to know how heavy your concrete really is? This guide walks you through concrete density, volume, and weight so you can plan transport, crane picks, slab demolition, and disposal like a pro. You’ll get clear formulas, ready-to-use tables, and real-world examples that match how contractors estimate in the field.
How the Concrete Weight Calculator works
The calculator multiplies density by volume. You pick a concrete type to prefill density. You enter volume in the units you prefer. The tool converts units behind the scenes and returns weight in your chosen unit.
- Concrete type sets a default density that matches typical industry values.
- Volume can be cubic feet, cubic yards, or cubic meters.
- Weight unit can be pounds, US tons, long tons, stones, kilograms, or metric tons.
You can overwrite density at any time if a mix design, ticket, or lab test gives you a project-specific value.
The formula: weight = density × volume
Concrete weight follows a single relationship that never changes.
Weight = Density × Volume
Keep your units consistent. If density uses pounds per cubic foot then volume must be in cubic feet. If you switch to cubic yards then convert density or let the calculator convert units for you.
Typical concrete densities by type
Fresh and hardened concrete fall into three broad bands: lightweight, normal weight, and heavyweight. Aggregates drive most of the change. Moisture, entrained air, and reinforcement nudge the number up or down.
| Concrete type | Typical density (lb/ft³) | kg/m³ | Notes |
|---|---|---|---|
| Asphalt concrete | ~145–150 | ~2320–2400 | Dense-graded HMA mixes cluster near 145 pcf in practice. See FHWA mix design guidance. |
| Portland cement concrete (normal weight) | ~140–150 | ~2240–2400 | Industry texts and DOT tables use 145 pcf as a solid estimating value. |
| Reinforced concrete | ~145–160 | ~2320–2560 | Steel increases weight slightly. Some agencies design with 150–160 pcf for conservative picks. |
| Concrete with limestone coarse aggregate | ~145–150 | ~2320–2400 | Limestone mixes often sit on the higher end of normal-weight density. |
| Concrete with gravel coarse aggregate | ~140–147 | ~2240–2350 | Rounded gravel can reduce unit weight a touch compared to crushed stone. |
| Structural lightweight concrete | ~90–120 | ~1440–1840 | Expanded shale, clay, or slate aggregates. See NRMCA CIP-36. |
Where do these numbers come from? Transportation and concrete industry guidance place normal-weight concrete near 140–150 pcf, with hot-mix asphalt around 145 pcf for common dense-graded mixes. Lightweight structural concrete sits lower by design. Sources include FHWA asphalt mix design manuals and NRMCA technical notes on density ranges. :contentReference[oaicite:0]{index=0}
What density should you use?
- Use 145 pcf (2320 kg/m³) for most quick estimates of normal-weight concrete.
- Use 150–160 pcf if your agency standard, crane chart, or engineer calls for reinforced assumptions. Some DOTs use 160 pcf for reinforced elements. :contentReference[oaicite:1]{index=1}
- Use your batch ticket or lab test if available. That trumps generic tables.
- For asphalt concrete on pavements, a 145 pcf default aligns with common DOT practice.
- For structural lightweight, use the value from the mix submittal, usually 90–120 pcf. :contentReference[oaicite:3]{index=3}
How to find concrete volume
Volume depends on shape. Measure the footprint then multiply by thickness or depth.
Slabs & pads
Volume = Length × Width × Thickness.
Keep all dimensions in the same unit before you multiply.
Beams
Volume = Width × Depth × Length.
Break tapered beams into segments for better accuracy.
Cylinders & piers
Volume = π × r² × Height.
Use radius in feet if density is in pounds per cubic foot.
Walls
Volume = Length × Height × Thickness.
Subtract openings for doors and windows if known.
Step-by-step examples
Example 1: Weight of a 10 ft × 10 ft patio slab, 4 in thick
- Volume in cubic feet: \( 10 × 10 × \tfrac{4}{12} = 33.33 \, \text{ft}^3 \).
- Density: assume 145 pcf for normal concrete.
- Weight: \( 33.33 × 145 ≈ 4,833 \) lb.
- US tons: divide by 2,000 → ~2.42 tons.
Example 2: Reinforced grade beam, 2 ft wide × 1.5 ft deep × 30 ft long
- Volume: \( 2 × 1.5 × 30 = 90 \, \text{ft}^3 \).
- Use 150 pcf to be conservative for rebar congestion.
- Weight: \( 90 × 150 = 13,500 \) lb → 6.75 US tons.
Example 3: Round pier, 24 in diameter × 10 ft tall
- Radius = 12 in = 1 ft.
- Volume: \( π × 1^2 × 10 = 31.416 \, \text{ft}^3 \).
- Weight at 145 pcf: \( 31.416 × 145 ≈ 4,555 \) lb.
Quick unit conversions
| From | To | Multiply by |
|---|---|---|
| Cubic yards → cubic feet | ft³ | 27 |
| Cubic meters → cubic feet | ft³ | 35.3147 |
| Cubic feet → cubic yards | yd³ | 0.037037 |
| From | To | Multiply by |
|---|---|---|
| Pounds → US tons | US ton | 0.0005 |
| Pounds → kilograms | kg | 0.45359237 |
| Kilograms → metric tons | t | 0.001 |
Frequently asked questions
Does wet concrete weigh more than cured concrete?
Yes. Fresh concrete carries mixing water that evaporates or hydrates as it cures. Equilibrium density drops a little as the slab dries. Normal-weight mixes still land near the 140–150 pcf band once cured. NRMCA’s guidance shows the contrast clearly for lightweight mixes where equilibrium density is a key design value. :contentReference[oaicite:4]{index=4}
Does rebar change the number?
Rebar increases weight because steel has a higher density than concrete. If a member has heavy reinforcement then using 150–160 pcf for quick picks is a conservative choice that many agencies adopt. :contentReference[oaicite:5]{index=5}
Is asphalt concrete lighter or heavier than Portland cement concrete?
Dense-graded asphalt concrete sits in the same ballpark as normal-weight PCC. Typical values run near 145 pcf. Mix design, air voids, and compaction change the final number.
Why does the same volume sometimes weigh more on my job?
Aggregate type, moisture, entrained air, and compaction each move the needle. Limestone and crushed stone tend to bump density. Rounded gravel and higher air contents nudge it lower. Water on a demolition site can add transient weight that isn’t present in design tables.
What density should I use for a disposal estimate?
Use the best available local number. If you have a mix ticket, use that. If not, default to 145 pcf for PCC or 145 pcf for dense-graded asphalt. If rebar is heavy or the element is a composite section then raise the assumption to 150–160 pcf.
Pro tips to improve accuracy
- Measure thickness at several spots. Slabs rarely stay perfectly uniform. Average your readings.
- Account for voids and openings. Subtract the volume of sleeves, blockouts, or core holes.
- Separate toppings and overlays. Treat each layer with its own density to avoid drift.
- Use the right unit conversions. Most errors start with inconsistent units. Double-check before you multiply.
- Lean conservative when lifting. Round density up for rigging or crane work since underestimating poses risk.
- Use equilibrium values for lightweight concrete. This aligns with industry practice for LWC design. :contentReference[oaicite:7]{index=7}
Technical sources and standards
The ranges above line up with long-standing industry practice and agency manuals. When you need a citation for a submittal, start here:
- FHWA Asphalt Mixture Design and field examples showing bulk specific gravity and typical asphalt concrete densities near 145 pcf. FHWA – Asphalt Mixture Design.
- NRMCA CIP-36: structural lightweight concrete equilibrium densities 90–120 pcf, contrasted with normal-weight 140–150 pcf. NRMCA CIP-36. :contentReference[oaicite:9]{index=9}
If your specifications point elsewhere then follow the project standard. Your ticketed unit weight always wins over generic values.
Glossary
- Density (unit weight): Mass or weight per unit volume. For concrete we typically use lb/ft³ or kg/m³.
- Equilibrium density: Density of lightweight concrete after moisture loss, used for structural design.
- Normal-weight concrete: Concrete made with sand and gravel or crushed stone that lands near 145 pcf.
- Asphalt concrete: Aggregate bound with bitumen. Often called HMA or “asphalt” in paving work.
- Reinforced concrete: Concrete with embedded steel bars, welded wire, or strands that carry tension.
How to use the calculator in under a minute
- Select a concrete type to prefill density. Leave it as is for quick estimates or replace with a ticket value.
- Enter volume. Use ft³ for small features, yd³ for large pours, m³ for international projects.
- Pick an output unit for weight. Pounds for demolition and hauling. US tons for trucking. Metric when needed.
- Read the result. Adjust density up for heavy reinforcement or down for higher entrained air if you have data.
Common mistakes to avoid
- Mixing units. A length in inches sneaks into a feet calculation and the result goes sideways.
- Using compacted asphalt field density for fresh asphalt in the truck. Your target depends on context.
- Ignoring moisture on demo jobs. A saturated slab weighs more than a dry estimate suggests.
Worked table: weight per cubic yard
| Density (lb/ft³) | Weight per yd³ (lb) | US tons per yd³ |
|---|---|---|
| 140 | 3,780 | 1.89 |
| 145 | 3,915 | 1.96 |
| 150 | 4,050 | 2.03 |
| 160 | 4,320 | 2.16 |
| 100 (lightweight) | 2,700 | 1.35 |
Multiply pounds by 0.0005 to convert to US tons. Divide by 2,000 if you like the mental math route.
When to adjust the default density
- Rebar congestion pushes weight up. Heavy mats and cages add steel mass.
- High entrained air in freeze-thaw mixes lowers unit weight slightly.
- Aggregate source matters. Limestone and basalt lean heavier than rounded river gravel.
- Moisture state matters during demo and disposal. Water in cracks and pores adds temporary weight.
Safety and logistics
Weight informs more than freight. It sets crane picks, shoring loads, and rigging plans. It determines dumpster size and truck count. Accurate numbers prevent reloads and extra trips. Good numbers also protect teams who depend on safe lifts.
Find volume. Pick a realistic density. Multiply. Convert units to match your vendor or spec. That’s the whole story. The calculator does the arithmetic so you can focus on the pour, the pick, or the plan.
