Concrete & Foundation

Concrete Weight Calculator — Pounds per Cubic Foot, Cubic Yard, kg per m³ by Mix Type with Dead Load Output

Q: How much does 1 cubic foot of concrete weigh?

Standard normal-weight concrete weighs 145 pounds per cubic foot (cured at standard humidity). Fresh / wet concrete runs 148–152 lb/ft³ (includes free water). Lightweight structural concrete (ACI PRC 213) drops to 105–115 lb/ft³ ; insulating lightweight to 30–90 lb/ft³ ; heavyweight radiation-shielding concrete jumps to 180–240 lb/ft³ . The 145 default in this calculator matches ACI 318-19 normal-weight specification and 90% of residential / light-commercial pours.

Q: How much does 1 cubic yard of concrete weigh?

Standard normal-weight: 3,915 pounds per cubic yard = 1.96 short tons (145 lb/ft³ × 27 ft³/yd³). A standard 10 yd³ ready-mix truck delivers ~40,500 lb of concrete plus the truck weighs ~26,000 lb = ~33 short tons GVWR . That's why ready-mix companies refuse to drive on residential lawns without ground-pressure mats — the truck will sink in soft soil. Plan ground-pressure paths and back-up access before scheduling the pour.

Q: How much does an 80-lb bag of concrete weigh after mixing?

An 80-lb bag of dry premix concrete needs about 3 quarts (6 lb) of water to reach proper consistency; the mixed bag weighs ~86 lb wet and yields 0.60 cubic feet of cured concrete. The water disappears chemically (combined with cement during hydration) and physically (evaporation during cure), but most of the mass stays — cured 80-lb bag yield weighs about 87 lb at 28 days. For 60-lb bags: ~67 lb wet, ~64 lb cured, 0.45 ft³ yield.

Q: What is concrete weight per square foot?

Multiply slab thickness in inches by 12.08 (for normal-weight 145 lb/ft³). Quick references: 4-in slab = 48.3 lb/sqft, 6-in = 72.5 lb/sqft, 8-in = 96.7 lb/sqft . For lightweight 110 lb/ft³, multiplier is 9.17; for 100 lb/ft³, 8.33. This number is what structural engineers use as the “concrete dead load” in IBC Table 1604.3 floor framing checks — the full table is in the slab dead-load section above.

Q: Will my floor support a concrete countertop or overlay?

Run the dead-load math first: weight (lb/sqft) = thickness (in) × 12.08 for normal-weight. A 1.5-in thick 145 lb/ft³ concrete countertop adds 18 lb/sqft of dead load — usually within the 10–15 lb/sqft dead-load reserve in residential floor framing per IRC R301.5. A 4-in concrete overlay adds 48.3 lb/sqft, almost certainly requiring framing reinforcement. The cutoff: up to 2-in normal-weight or 3-in lightweight is usually safe on existing residential framing ; anything thicker needs a structural review. When in doubt, switch to lightweight (saves 24% dead load) or thin the overlay.

Q: Why does concrete weigh so much?

Concrete is mostly aggregate (60–80% of volume) — crushed limestone, gravel and sand — which has the same density as natural rock (~165 lb/ft³ in solid form, ~95–100 lb/ft³ in compacted aggregate-only state). Mixing with cement paste, water and air fills the voids and binds it together; the resulting composite is 145 lb/ft³ normal-weight. The 145 number is essentially the weight of crushed rock plus the cementitious paste that glues it together. Switching aggregate to expanded shale / clay (lightweight) drops the aggregate weight 40% which pulls the composite down to 105–115 lb/ft³.

Estimate concrete weight in lb/ft³, lb/yd³, kg/m³ and total slab dead load for any pour. Includes 8 mix-type density presets (normal weight, lightweight, heavyweight, fiber-reinforced) calibrated to ASTM C138 + ACI PRC 213 + AASHTO T 121, plus the IBC Table 1604.3 dead-load reference that engineers use to size joists, slabs and floor framing.

Edited by Sarah Miller, Construction Content Editor

Technically reviewed by Michael Carter, Concrete & Foundation Estimation Specialist (15 yrs)

Published 2026-05-26 · Updated 2026-05-26 · Technically reviewed 2026-05-26

Concrete Weight Calculator

Enter project dimensions below — results update instantly. Switch units freely.

Try a real example:

Surface Area 0 ft²

Volume 0 yd³

Total Weight 0 lb

Total Weight (tons) 0 short tons

Total Weight (kg) 0 kg

Dead Load per sqft 0 lb/ft²

Density 0 lb/yd³

Density (metric) 0 kg/m³

Estimates assume typical industry density and waste factors. Always verify with your supplier and local building code before purchasing material.

Why this matters

Why ‘Concrete Weighs 150 lb/ft³’ Is a Half-Truth

Every site you visit will quote “concrete weighs 150 pounds per cubic foot” — including this one, sometimes. That number is correct for one specific case: normal-weight concrete with normal-weight aggregate, fresh / wet, at standard density. The actual weight of concrete in your project can be anywhere from 90 lb/ft³ (structural lightweight) up to 240 lb/ft³ (heavyweight for radiation shielding) — a 2.7× range that decides whether your floor framing carries the load or fails inspection.

Three variables determine the actual answer:

Aggregate type — normal-weight aggregate (crushed limestone, gravel) gives 140–150 lb/ft³ mixes; expanded shale / clay (lightweight) drops to 90–115 lb/ft³ (ACI PRC 213); barite / magnetite (heavyweight) jumps to 200–240 lb/ft³.
Moisture state — fresh (wet) concrete weighs 145–152 lb/ft³; cured at 50% relative humidity drops to 142–148 lb/ft³ (water of hydration evaporates); oven-dry (lab) measurement gives 138–145 lb/ft³.
Mix-specific density — air-entrained mixes (6–7% air) drop 4–6 lb/ft³ vs same mix without air. Fiber-reinforced adds 2–4 lb/ft³. Self-consolidating concrete (SCC) is in-spec at 142–148 lb/ft³.

The calculator above lets you pick mix type from a preset list (or input a custom density) and outputs weight in lb/ft³, lb/yd³, kg/m³ PLUS total project dead load in pounds and short tons. The default 145 lb/ft³ (cured normal-weight) is what you want for 90% of residential and light-commercial pours; switch to 110 lb/ft³ if you're working with a true structural lightweight mix and to 90–100 lb/ft³ for insulating-only lightweight.

The formula

The Concrete Weight Formula and ASTM C138 Reference Densities

Weight_lb = L × W × D_ft × Density_lb/ft³
lb/yd³ = Density_lb/ft³ × 27
kg/m³ = Density_lb/ft³ × 16.018

Conversion factors: 1 yd³ = 27 ft³; 1 lb/ft³ = 16.018 kg/m³ (per NIST handbook). For metric input, the calculator runs the inverse conversion automatically.

Density by Mix Type (ACI 318, ACI PRC 213, ASTM C138)

Concrete Density Reference Table by Mix Family (ASTM C138 unit weight test)
Mix family	lb/ft³ (cured)	lb/yd³	kg/m³	Typical PSI	Where used
Standard normal-weight	145	3,915	2,323	3,000–5,000	Residential slabs, sidewalks, footings — the default
High-strength normal-weight	148–152	3,996–4,104	2,371–2,435	5,000–10,000	Commercial columns, pre-stressed beams
Air-entrained normal-weight	140–144	3,780–3,888	2,243–2,307	3,000–5,000	Freeze-thaw exposed slabs, driveways in cold climates
Fiber-reinforced normal-weight	146–148	3,942–3,996	2,339–2,371	3,500–5,000	Slabs with synthetic / steel fiber for crack control
Structural lightweight (ACI PRC 213)	105–115	2,835–3,105	1,682–1,842	3,000–5,000	Composite floor decks, precast lightweight beams
Insulating lightweight	30–90	810–2,430	481–1,442	100–1,000	Roof deck insulation fill, thermal mass
Heavyweight (barite / magnetite)	180–240	4,860–6,480	2,883–3,845	3,000–5,000	Radiation shielding (medical, nuclear), counter-weights
Self-consolidating (SCC)	142–148	3,834–3,996	2,275–2,371	4,000–7,000	Heavily reinforced sections where vibration is impractical

Source: ASTM C138 standard unit weight test (slump cone fresh density), ACI 318-19 normal-weight definition (≥ 135 lb/ft³), ACI PRC 213 structural lightweight definition (90–115 lb/ft³). ‘Cured’ densities are oven-dry equivalents per ASTM C642; fresh densities run 2–5 lb/ft³ higher.

Concrete Weight Per Square Foot (by Slab Thickness)

Concrete Slab Dead Load by Thickness (normal-weight 145 lb/ft³)
Slab thickness	lb/sqft	kg/m²	10x10 ft slab weight	Typical use
2 in	24.2	118	2,420 lb (1.2 ton)	Topping slab
3 in	36.3	177	3,625 lb (1.8 ton)	Walkway, garage prep
4 in	48.3	236	4,830 lb (2.4 ton)	Standard residential slab, sidewalk
5 in	60.4	295	6,040 lb (3.0 ton)	Garage, light commercial floor
6 in	72.5	354	7,250 lb (3.6 ton)	Driveway, commercial floor, apron
8 in	96.7	472	9,665 lb (4.8 ton)	Heavy-load commercial floor, truck zone
10 in	120.8	590	12,080 lb (6.0 ton)	Pre-engineered metal building floor
12 in	145.0	708	14,500 lb (7.3 ton)	Footing, retaining wall, industrial floor

Multiplier: weight per sqft = thickness in inches × 12.083 (for 145 lb/ft³ normal-weight). For lightweight 110 lb/ft³, multiplier = 9.17; for 100 lb/ft³, multiplier = 8.33. The IBC 2024 Table 1604.3 dead-load reference for “concrete, plain or reinforced” is the 12.08-times-thickness-in-inches rule for normal-weight.

Concrete Bag & Truck Weight Reference

Practical numbers you actually need when ordering and handling concrete:

60-lb bag (Quikrete / Sakrete dry mix) — yields 0.45 ft³ cured; weighs 60 lb dry, ~67 lb wet (water added on site, ~7 lb / bag)
80-lb bag — yields 0.60 ft³ cured; weighs 80 lb dry, ~90 lb wet
1 cubic yard ready-mix truck capacity — ~4,050 lb of 4,000 psi normal-weight concrete (2.0 short tons), takes ~10 minutes to pour
10 cubic yard standard truck — ~40,500 lb of concrete plus 26,000 lb truck = ~33 short tons total GVWR — that's why you'll see the truck driver check ground compaction before backing onto your lawn

AI-era engineering pitfall guide

What Most Online Calculators Get Wrong Reviewed by Michael Carter, Concrete & Foundation Estimation Specialist (15 yrs)

Most online concrete weight calculators give one number (145 lb/ft³) and stop. Three pitfalls cause every gap I see between calculator output and structural reality:

Single-density assumption ignores air entrainment. 90% of online concrete weight calculators hardcode 145 lb/ft³ and call it done. The actual density of an air-entrained 4,000 psi mix (the standard freeze-thaw exposed spec) is 140–142 lb/ft³, not 145. On a 10-cubic-yard driveway pour, that's 1,080 lb of weight you don't actually have — not a structural issue at the slab level but it does shift truck-delivery math by ~2.5% per load. Always confirm the air-entrainment spec off the supplier's mix design submittal.
Fresh vs cured vs oven-dry density. The ASTM C138 unit weight test runs on fresh / wet concrete at the chute; that number is 148–152 lb/ft³. Cured concrete at 50% RH loses ~3 lb/ft³ of free water; oven-dry (ASTM C642) loses another ~3 lb/ft³. Most online calculators don't tell you which they're using. The right number for dead-load calculations is cured density: 145 lb/ft³ normal-weight, 110 lb/ft³ structural lightweight. Don't use fresh-state density for floor-framing checks — you'll over-spec the framing by 5%.
The ACI 318 contrarian view: lightweight is over-specified. Mark Suprenant of ACI Committee 213 has argued at recent conferences that most residential concrete countertops and overlay projects don't need lightweight aggregate — the typical 1.5-in countertop adds 18 lb/sqft dead load in normal-weight, which is within the residential dead-load reserve. Specifying lightweight ($30–$70/yd³ premium) for a 1.5-in countertop is a 15% cost premium for 4 lb/sqft of weight reduction. The honest decision: spec lightweight only when you cross the dead-load threshold (typically 2-in normal-weight or thicker over existing framing).

Field note from Michael Carter, Concrete & Foundation Estimation Specialist (15 yrs)

On a converted-attic project in Wilmington DE (June 2024) the homeowner wanted a 4-in thick concrete countertop overlay (12 ft × 30 in × 4 in). Sounded innocuous — until I ran the dead-load math: 12 × 2.5 × 0.33 × 145 = 1,440 lb of concrete, plus 200 lb of metal frame and reinforcement = 1,640 lb on a span the homeowner had no idea about. The 2x10 floor joists below it were rated for 50 lb/sqft live load + 10 lb/sqft dead — the 30 sqft countertop area would have added 55 lb/sqft of dead load alone, overloading the joists by 30%. We pivoted to a 1-in concrete overlay (360 lb total, ~12 lb/sqft) on a 3/4-in plywood backer, hitting the same aesthetic without the structural reinforcement. Saved the homeowner $3,200 in floor framing work and 4 weeks of delays. Lesson: always run the weight-per-square-foot math before committing to a thickness, especially on retrofit / overlay projects where you don't get a structural engineer.

Concrete Weight Coverage Table and Material Reference

Concrete Volume → Weight Quick Reference (normal-weight 145 lb/ft³)
Volume	Weight (lb)	Weight (short tons)	Weight (kg)	Number of 80-lb bags equivalent
1 ft³	145	0.073	65.8	1.67
10 ft³	1,450	0.73	658	16.7
1 yd³	3,915	1.96	1,776	45
5 yd³	19,575	9.8	8,882	225
10 yd³	39,150	19.6	17,765	450
1 m³	5,122	2.56	2,323	59
100 sqft × 4 in	4,830	2.4	2,192	55
1,000 sqft × 6 in	72,500	36.3	32,886	830

For lightweight 110 lb/ft³ mixes, multiply by 0.76; for heavyweight 220 lb/ft³ mixes, multiply by 1.52. Bag count assumes 80-lb bags at 0.60 ft³ yield.

Concrete vs Common Construction Materials Weight Reference
Material	lb/ft³	lb/yd³	Relative to concrete (1.0×)
Normal-weight concrete	145	3,915	1.0× baseline
Structural lightweight concrete	110	2,970	0.76×
Steel (structural A36)	490	13,230	3.4×
Brick (clay)	120	3,240	0.83×
Concrete masonry (CMU)	85–135	2,295–3,645	0.59–0.93×
Wood (Douglas fir)	35	945	0.24×
Asphalt (HMA)	145	3,915	1.0× (same)
Topsoil (dry)	75	2,025	0.52×
Gravel (crushed)	100	2,700	0.69×
Water	62.4	1,685	0.43×

Cross-reference: concrete and HMA have essentially identical bulk density. Steel is 3.4× heavier than concrete per cubic foot — which is why steel beams transfer concrete loads to columns rather than steel plates carrying concrete-equivalent volumes.

Real-World Example Calculations

Worked Example 1: 16x16 ft Patio Slab Dead Load

Homeowner pouring a 16 ft × 16 ft × 4 in concrete patio in Newark DE. Wants to know how much weight it adds to the existing house footing perimeter and total concrete weight.

Length: 16 ft
Width: 16 ft
Thickness: 4 in
Mix type: Standard normal-weight (145 lb/ft³)

Weight 12,373 lb (6.2 short tons) / 3.16 yd³ / 5,612 kg total

Takeaway: At 4-in thickness the slab dead load is 48.3 lb/sqft — well within the residential floor framing capacity (50 lb/sqft live + 10 lb/sqft dead = 60 lb/sqft total in IRC). Patio is on grade (not on framing) so the dead load goes into the compacted base; sub-grade should be 6 in compacted crushed stone to spread the 6-ton load uniformly.

Worked Example 2: Lightweight Concrete Floor Topping (Loft Conversion)

Loft conversion adding a 1-in lightweight concrete topping over existing 3/4-in plywood floor sheathing for radiant floor heat. Span 14 ft x 20 ft. Need to verify dead-load fits joist capacity.

Length: 14 ft
Width: 20 ft
Thickness: 1 in
Mix type: Insulating lightweight (90 lb/ft³)

Weight 2,100 lb (1.05 short tons) / 0.78 yd³ / 953 kg total

Takeaway: Total added dead load = 2,100 lb / 280 sqft = 7.5 lb/sqft. Sits within the typical 10 lb/sqft dead-load reserve in IRC R301.5. If the homeowner had picked 1-in normal-weight (145 lb/ft³) instead, the load would have been 12.1 lb/sqft — over the dead-load budget by 21% and triggering a structural review. Lightweight made the difference between go and stop.

Worked Example 3: 200 ft Driveway 6-in Slab — Total Order Weight

Driveway pour 200 ft x 12 ft x 6 in standard 4,000 psi air-entrained concrete (freeze-thaw climate). Verify total weight to plan truck deliveries and ground-pressure on sub-grade.

Length: 200 ft
Width: 12 ft
Thickness: 6 in
Mix type: Air-entrained normal-weight (142 lb/ft³)

Weight 170,400 lb (85.2 short tons) / 44.4 yd³ / 77,295 kg total

Takeaway: 44.4 yd³ of concrete = 5 full ready-mix trucks (10 yd³ each) over 1.5–2 days. Each truck delivers ~40,000 lb of concrete plus 26,000 lb truck = 66,000 lb GVWR; coordinate with sub-grade compaction so trucks don't rut. Air-entrained drops density by 3 lb/ft³ vs straight 145 baseline but is non-negotiable for freeze-thaw exposed slabs (saves 15–20 yr of service life).

Sources & Standards

These references are used for terminology, safety boundaries, and engineering assumptions. Local code, supplier specifications, and licensed design documents still control your project.

ASTM C138/C138M-23: Standard Test Method for Density (Unit Weight), Yield, and Air Content of Concrete ASTM International
Referenced for the fresh-state unit weight test procedure that establishes the lb/ft³ density values quoted in the comparison table.
ACI 318-19: Building Code Requirements for Structural Concrete American Concrete Institute
Referenced for the normal-weight concrete density definition (≥ 135 lb/ft³ by ACI 318 Section 19.2.4) used in the calculator default and the high-strength range.
ACI PRC-213-23: Report on Lightweight Concrete American Concrete Institute
Referenced for the structural lightweight concrete density range (90–115 lb/ft³) and the insulating lightweight range used in the lightweight presets.
IBC 2024 Table 1604.3 — Deflection and Dead Load Reference International Code Council
Referenced for the concrete dead-load (12.08 × thickness-in-inches lb/sqft) values used to verify slab and floor framing capacity.
AASHTO T 121M/T 121: Standard Method of Test for Density (Unit Weight) of Concrete American Association of State Highway and Transportation Officials
Referenced for the alternate density measurement procedure used in DOT and bridge-deck concrete specifications, cross-checked against ASTM C138.

Frequently Asked Questions

How much does 1 cubic foot of concrete weigh?

Standard normal-weight concrete weighs 145 pounds per cubic foot (cured at standard humidity). Fresh / wet concrete runs 148–152 lb/ft³ (includes free water). Lightweight structural concrete (ACI PRC 213) drops to 105–115 lb/ft³; insulating lightweight to 30–90 lb/ft³; heavyweight radiation-shielding concrete jumps to 180–240 lb/ft³. The 145 default in this calculator matches ACI 318-19 normal-weight specification and 90% of residential / light-commercial pours.

How much does 1 cubic yard of concrete weigh?

Standard normal-weight: 3,915 pounds per cubic yard = 1.96 short tons (145 lb/ft³ × 27 ft³/yd³). A standard 10 yd³ ready-mix truck delivers ~40,500 lb of concrete plus the truck weighs ~26,000 lb = ~33 short tons GVWR. That's why ready-mix companies refuse to drive on residential lawns without ground-pressure mats — the truck will sink in soft soil. Plan ground-pressure paths and back-up access before scheduling the pour.

How much does an 80-lb bag of concrete weigh after mixing?

An 80-lb bag of dry premix concrete needs about 3 quarts (6 lb) of water to reach proper consistency; the mixed bag weighs ~86 lb wet and yields 0.60 cubic feet of cured concrete. The water disappears chemically (combined with cement during hydration) and physically (evaporation during cure), but most of the mass stays — cured 80-lb bag yield weighs about 87 lb at 28 days. For 60-lb bags: ~67 lb wet, ~64 lb cured, 0.45 ft³ yield.

What is concrete weight per square foot?

Multiply slab thickness in inches by 12.08 (for normal-weight 145 lb/ft³). Quick references: 4-in slab = 48.3 lb/sqft, 6-in = 72.5 lb/sqft, 8-in = 96.7 lb/sqft. For lightweight 110 lb/ft³, multiplier is 9.17; for 100 lb/ft³, 8.33. This number is what structural engineers use as the “concrete dead load” in IBC Table 1604.3 floor framing checks — the full table is in the slab dead-load section above.

How much does lightweight concrete weigh?

Structural lightweight concrete (ACI PRC 213): 105–115 lb/ft³, used in composite floor decks and precast lightweight beams; reaches 3,000–5,000 psi. Insulating lightweight: 30–90 lb/ft³, used for roof deck thermal-mass and lightweight fill; reaches 100–1,000 psi (not structural). The distinction matters: structural lightweight can carry loads; insulating lightweight cannot. Both use expanded shale, clay, or perlite aggregate instead of crushed limestone / gravel.

Will my floor support a concrete countertop or overlay?

Run the dead-load math first: weight (lb/sqft) = thickness (in) × 12.08 for normal-weight. A 1.5-in thick 145 lb/ft³ concrete countertop adds 18 lb/sqft of dead load — usually within the 10–15 lb/sqft dead-load reserve in residential floor framing per IRC R301.5. A 4-in concrete overlay adds 48.3 lb/sqft, almost certainly requiring framing reinforcement. The cutoff: up to 2-in normal-weight or 3-in lightweight is usually safe on existing residential framing; anything thicker needs a structural review. When in doubt, switch to lightweight (saves 24% dead load) or thin the overlay.

Why does concrete weigh so much?

Concrete is mostly aggregate (60–80% of volume) — crushed limestone, gravel and sand — which has the same density as natural rock (~165 lb/ft³ in solid form, ~95–100 lb/ft³ in compacted aggregate-only state). Mixing with cement paste, water and air fills the voids and binds it together; the resulting composite is 145 lb/ft³ normal-weight. The 145 number is essentially the weight of crushed rock plus the cementitious paste that glues it together. Switching aggregate to expanded shale / clay (lightweight) drops the aggregate weight 40% which pulls the composite down to 105–115 lb/ft³.

How does air entrainment affect concrete weight?

Air-entrained concrete (6–7% air by volume) drops density by 3–5 lb/ft³ vs the same mix without air. Normal-weight standard mix drops from 145 to 140–142 lb/ft³ with air entrainment. The trade is intentional: air voids give the concrete room to absorb freeze-thaw expansion without cracking. In any climate that sees freezing temperatures, air-entrained mixes (4,000 psi, 6–7% air per ACI 318) are non-negotiable for exposed slabs — the 3 lb/ft³ weight saving is incidental.