Concrete Floor Calculator

Calculate concrete volume, bags, weight, cost, and reinforcement for any concrete floor project.

Units
Imperial Metric
Enter floor length Enter a valid length
Enter floor width Enter a valid width
Residential: 4 in · Garage: 5–6 in · Commercial: 6–8 in Enter a valid thickness
Typically 5–10%
Leave blank to skip
Live 3D Preview
Results
Concrete needed –
In cubic feet –
In cubic metres –
Floor area –
With waste (10%) –
Concrete weight –
60 lb bags needed –
80 lb bags needed –
Ready-mix trucks (8 yd³) –
Recommended PSI –
Reinforcement –
How to Use

1. Select your floor type to get a recommended thickness and PSI guidance.

2. Enter length and width in feet (or metres if Metric is selected).

3. Enter the slab thickness — the hint text shows standard values for each floor type.

4. Adjust the waste factor (default 10%) to account for spillage and uneven subgrade.

5. Optionally enter a concrete price per cubic yard to get an instant cost estimate.

6. Results update live. Click Download PDF Report for a branded project report.

Formula Used

Volume (cu ft)

Volume (ft³) = Length (ft) × Width (ft) × Thickness (ft)
where Thickness (ft) = Thickness (in) ÷ 12

Conversions

Cubic Yards = ft³ ÷ 27
Cubic Metres = ft³ × 0.0283168
Volume with Waste = cu yd × (1 + waste% ÷ 100)
Weight (lb) = cu ft × 150.23  [normal-weight concrete 150 lb/ft³]
60 lb bags = ⌈ (ft³ with waste) ÷ 0.45 ⌉
80 lb bags = ⌈ (ft³ with waste) ÷ 0.60 ⌉
Floor Type Guide — Thickness & PSI Reference
Floor Type Thickness PSI Reinforcement
Residential Slab4 in (100 mm)3,000 PSI#3 rebar @ 18″ o/c or 6×6 WWM
Garage Floor5–6 in (125–150 mm)3,500 PSI#4 rebar @ 12–18″ o/c
Basement Floor4 in (100 mm)3,000 PSI6×6 W1.4×W1.4 WWM
Patio & Walkway4 in (100 mm)3,000–3,500 PSI#3 rebar @ 18–24″ o/c
Commercial Floor6–8 in (150–200 mm)4,000–4,500 PSI#4–#5 rebar @ 12″ o/c

Always consult your local building code and structural engineer for load-bearing applications.