Concrete Slab Calculator
Calculate cubic yards of concrete, bag count, rebar reinforcement, and total installed costs for patios, sheds, and foundations.
Concrete Slab Calculator
01 // PROJECT SPECIFICATIONS
Length of the concrete pad in feet
Width of the concrete pad in feet
Standard 4" depth handles residential pedestrian loads
Optional hydraulic breaker demolition and rubble haul-away
02 // MATERIAL GRADE SELECTION
03 // REGIONAL LABOR MARKET TIER
03 // SPECIFICATION TAKEOFF & LINE-ITEM BREAKDOWN
Ready-mix concrete volume basis + basic formwork lumber (scales with slab thickness) (4" slab volume: 1.36 cu yd ready-mix)
Excavation grading, form building, pour, strike-off, and float/broom finishing
Standard residential municipal building inspection permit
Excavated earth and formwork waste disposal allowance
| Cost Component | Notes & Rate Basis | Estimated Amount |
|---|---|---|
| Standard Concrete Mix (3000 PSI) | Ready-mix concrete volume basis + basic formwork lumber (scales with slab thickness) (4" slab volume: 1.36 cu yd ready-mix) Benchmark ready-mix 3000 PSI concrete volume rate ($135–$150/cu yd) plus 2x4 edge formwork lumber allowance ($0.35/sq ft) calibrated against national retail listings. | $231 |
| Professional Trade Labor | Excavation grading, form building, pour, strike-off, and float/broom finishing Derived from the May 2024 BLS OEWS national median wage ($28.80/hr) for SOC 47-2051, billed at 0.055 hours per square foot with standard contractor labor burden and crew overhead. | $374 |
| Building Permit & Municipal Inspections | Standard residential municipal building inspection permit National benchmark average for residential municipal building permits and pre-pour structural setback/formwork inspection fees ($100–$200 range). | $150 |
| Debris Disposal & Haul-Away | Excavated earth and formwork waste disposal allowance Allowance for excavated soil spoil hauling, formwork lumber tear-down disposal, and site backfilling ($0.30–$0.40/sq ft). | $39 |
| Total Project Estimate | $794 | |
What's included in this estimate
- –Concrete pump truck dispatch ($400–$700 minimum dispatch) when delivery trucks cannot pull within chute distance (20–25 ft)
- –Existing concrete demolition and tear-out (breaking up and hauling away old concrete adds $1.75/sq ft, unless add-on is selected)
- –Thickened perimeter footings for heavy-duty structures
- –Power trowel machine finishing
- ·Standard 4-inch unreinforced slab (3000 PSI) for pedestrian walkways, outdoor dining patios, or small garden sheds ($2.10/sq ft materials)
- ·Direct chute placement where ready-mix concrete delivery trucks can pull within chute distance (20–25 ft)
- ·Rural or lower-cost regional labor market (0.85× multiplier)
- ·DIY self-installation for small pads under 150 sq ft (40% to 50% savings by eliminating contractor labor)
- ·Increasing slab thickness from 4 inches to 6 inches for heavy vehicles or machinery (+50% more concrete volume, +$0.75 to $1.65/sq ft)
- ·Upgrading from unreinforced concrete to #4 steel rebar grid on chairs ($3.75/sq ft materials for 4000 PSI + rebar)
- ·High-cost or premium metropolitan labor market (1.20× to 1.40× in NYC, San Francisco, Boston)
- ·Demolition and tear-out of existing damaged concrete pads (+$1.75/sq ft for hydraulic breakers and recycling dumpsters)
- ·Adding a 4-inch compacted crushed stone gravel base and 6-mil polyethylene plastic vapor retarder (+$1.00 to $2.00/sq ft)
When ready-mix concrete delivery trucks cannot pull within chute distance (20–25 ft) of the slab location, a concrete pump truck operator is required ($400–$700 minimum dispatch, $120–$180/hr).
Replacing cracked, uneven existing concrete requires hydraulic breaker jackhammering, rubble haulage, and disposal dumpsters, adding $1.75 per square foot.
Ready-mix batch plants enforce a minimum dispatch charge of 3 to 4 cubic yards, adding short-load fees of $100 to $250 for pours under 2 cubic yards unless mixed from bags on site.
Unreinforced slabs in severe frost-heave soils are susceptible to cracking; code-compliant structures often mandate heavy-duty slabs with thickened perimeter footings.
Pouring a small shed pad under 150 sq ft using bagged concrete and a rented mixer eliminates contractor trade labor, saving 40% to 50% ($1,400 to $1,800 on a 400 sq ft equivalent).
Check this estimate yourself
Verify our benchmark numbers against the same primary sources we use for materials, labor, and local permitting:
Calculation Formula & Engineering Rules
Our estimating engine calculates required volume or surface area from your project dimensions, applies verified unit material prices, adds trade-standard waste allowances, and adjusts labor, permit, and disposal components for regional economic variations:
Total Cost = Material Costs + [(Labor + Permits + Disposal) ×
Regional Multiplier] Worked Estimating Example: Baseline Specification
ENGINE BASELINE OUTPUTBelow is a fully itemized breakdown for a typical residential project configured with our default baseline dimensions ( 10 ft × 10 ft (4 in thickness)) using standard national benchmark pricing in an average-cost US market:
| Cost Component | Category | Amount ($) | Share of Total | ||
|---|---|---|---|---|---|
| Cost Component & Scope | Amount · Share | ||||
| materials Standard Concrete Mix (3000 PSI) Ready-mix concrete volume basis + basic formwork lumber (scales with slab thickness) (4" slab volume: 1.36 cu yd ready-mix) | $231.00 · 29.1% | Standard Concrete Mix (3000 PSI) Ready-mix concrete volume basis + basic formwork lumber (scales with slab thickness) (4" slab volume: 1.36 cu yd ready-mix) | materials | $231.00 | 29.1% |
| labour Professional Trade Labor Excavation grading, form building, pour, strike-off, and float/broom finishing | $374.00 · 47.1% | Professional Trade Labor Excavation grading, form building, pour, strike-off, and float/broom finishing | labour | $374.00 | 47.1% |
| permit Building Permit & Municipal Inspections Standard residential municipal building inspection permit | $150.00 · 18.9% | Building Permit & Municipal Inspections Standard residential municipal building inspection permit | permit | $150.00 | 18.9% |
| disposal Debris Disposal & Haul-Away Excavated earth and formwork waste disposal allowance | $38.50 · 4.9% | Debris Disposal & Haul-Away Excavated earth and formwork waste disposal allowance | disposal | $38.50 | 4.9% |
| Total Estimated Baseline Cost | $793.50 · 100.0% | ||||
|
National Contractor Range (110 sq ft)
$695 – $920 (
$7.21/sq ft & cu yd)
| |||||
| Total Estimated Baseline Cost | $793.50 | 100.0% | |||
| National Contractor Range (110 sq ft) | $695 – $920 ( $7.21/sq ft & cu yd) | ||||
Material Grades & National Supplier Pricing
Unit material pricing sourced from verified national suppliers (Home Depot, Lowe's, and specialty regional building distributors) as of 2026-10-22:
| Material Grade | Unit Price | Specification & Recommended Use Case | ||
|---|---|---|---|---|
| Material Grade & Specification | Unit Price | |||
| Standard Concrete Mix (3000 PSI) Ready-mix concrete volume basis + basic formwork lumber (scales with slab thickness) | $2.10 / sqft | Standard Concrete Mix (3000 PSI) | $2.10 / sqft | Ready-mix concrete volume basis + basic formwork lumber (scales with slab thickness) |
| Reinforced Concrete (Wire Mesh / #4 Rebar) Ready-mix concrete + steel reinforcement grid & vapor barrier (scales with slab thickness) | $2.85 / sqft | Reinforced Concrete (Wire Mesh / #4 Rebar) | $2.85 / sqft | Ready-mix concrete + steel reinforcement grid & vapor barrier (scales with slab thickness) |
| High-Strength Heavy-Duty (4000+ PSI + Rebar Grid) Commercial-grade ready-mix concrete + heavy #4 rebar grid for heavy vehicles & equipment | $3.75 / sqft | High-Strength Heavy-Duty (4000+ PSI + Rebar Grid) | $3.75 / sqft | Commercial-grade ready-mix concrete + heavy #4 rebar grid for heavy vehicles & equipment |
DIY vs. Professional Contractor Installation
DIY APPROACH
Best suited for experienced homeowners with proper specialty tools. Saves direct professional labor costs (typically 40% to 55% of the total contractor invoice). Requires significant physical stamina, site preparation, safety gear, tool rental expenses, and material hauling logistics.
HIRING A LICENSED CONTRACTOR
Recommended for structural integrity, code-compliant permitting, heavy demolition, and expedited completion. Professional contractors carry commercial general liability and workers' compensation insurance, provide manufacturer-backed workmanship warranties, and handle municipal building inspections.
Need an In-Depth Cost Analysis?
Explore our comprehensive cost guide for complete material comparisons, contractor negotiation tips, and local permit advice.
Frequently Asked Questions About Concrete Slab Calculator
How thick should my concrete slab be (4 inches vs 6 inches)? ↓
A 4-inch concrete slab is the standard thickness for residential applications such as patios, walkways, and light storage sheds. A 5-inch to 6-inch thickness with rebar reinforcement is recommended for heavy loads, including RV parking pads, detached garages, heavy machinery workshops, and hot tub foundations.
How many cubic yards of concrete do I need for my slab? ↓
Concrete volume is measured in cubic yards. The formula is (Length in ft × Width in ft × Thickness in ft) ÷ 27. For example, a 10×10 ft slab at 4 inches (0.333 ft) equals 1.23 cubic yards before waste. Adding our recommended 10% safety allowance results in 1.36 cubic yards to order.
Why does the calculator include a 10% concrete waste allowance? ↓
A 10% overage allowance accounts for subgrade settling, uneven excavation depth, slight form board deflection under hydrostatic pressure, and concrete left inside the transit mixer chute or pump truck hopper.
Can I pour a concrete slab as a DIY project or should I hire a pro? ↓
Small slabs under 100 square feet (such as trash can pads or small sidewalk sections) are manageable DIY projects using bagged concrete and a rented mixer. Pours exceeding 100 square feet require transit ready-mix delivery, rapid screeding, bull floating, and timely joint cutting before the concrete initial set, making professional crews highly advisable.
Do I need a building permit to pour an exterior concrete slab? ↓
Most municipalities require building permits if the slab exceeds 100–200 square feet, connects structurally to your home foundation, alters property drainage patterns, or will support a permanent enclosed structure like a detached garage.
How much does old concrete demolition and tear-out cost? ↓
Old slab demolition typically costs $1.50 to $2.50 per square foot ($1.75 standard benchmark) for hydraulic breaker or jackhammer breaking, hauling, and concrete recycling disposal fees.