Slab Calculator
Typical: 4 in (patio), 6 in (driveway)
Price per yd³
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Slab Results
Cubic Yards
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yd³ (w/ waste factor)
Cubic Feet
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ft³
Ready-Mix Cost
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estimated material
60 lb Bags
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bags needed
80 lb Bags
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bags needed
Surface Area
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square feet total
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Concrete Mix 80 lb bags (Quikrete / Sakrete)
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Crushed Gravel Base (4" base layer)
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Wire Mesh 6×6 Sheets OR Rebar #4
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2×6 Form Boards (perimeter)
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6 mil Poly Sheeting (vapor barrier)
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Concrete Sealer (apply after 28 days)
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⚠️ Always order 10% extra. Stopping mid-pour creates cold joints that weaken the slab structurally.
Slab Thickness Reference
| Application | Min Thickness | Recommended | PSI |
|---|---|---|---|
| Sidewalk / Walkway | 3" | 4" | 3000 |
| Backyard Patio | 3.5" | 4" | 3000–4000 |
| Residential Driveway | 4" | 5" | 4000 |
| Garage Floor | 4" | 5–6" | 4000 |
| Heavy Equipment Pad | 6" | 8" | 5000 |
Slab Thickness by Use Case
How thick should your concrete slab be? Code-recommended dimensions for any project
| Application | Min Thickness | Recommended | Reinforcement |
|---|---|---|---|
| Sidewalk / Walkway | 3.5" | 4" | Optional fiber |
| Patio | 4" | 4" | Mesh recommended |
| Residential Driveway | 4" | 5" | Mesh or rebar grid |
| Garage Floor | 4" | 5–6" | Rebar grid required |
| RV/Truck Pad | 6" | 6–8" | Heavy rebar grid |
| Shed Foundation (small) | 4" | 4" | Mesh |
| Pool Deck | 4" | 4–5" | Mesh + control joints |
| Hot Tub Pad | 4" | 6" | Rebar grid |
For freeze-thaw climates (Northeast, Midwest, Mountain West), add 1 inch to the recommended thickness. Always check your local building code — some jurisdictions require 6" minimum for driveways regardless of use.
Slab Pour Checklist
A repeatable order-of-operations that prevents the most common DIY slab mistakes
- Excavate to depth. Slab thickness + base depth + 2" for forms = total dig depth. For a 4" slab on 4" base, dig 10" below final grade.
- Compact subgrade. Native soil should be compacted to 95% before adding base. Don't skip this on clay or recently disturbed soil.
- Lay 4" of crushed stone or roadbase. Compact in 2" lifts. 95% compaction is the target.
- Set forms. 2x4 lumber for 3.5" slabs, 2x6 for 5" slabs. Stake every 4 feet. Check for level and proper slope (¼" per foot away from buildings).
- Place vapor barrier and reinforcement. 6 mil poly under interior slabs. Wire mesh or rebar grid raised 1.5–2" off the base on chairs.
- Pour and screed. Pour from far end working back. Screed level with the forms using a 2x4. Don't over-work the surface.
- Float, edge, and joint. Bull float once water sheen disappears. Edge the perimeter with an edging tool. Cut control joints every 8–10 feet.
- Final finish and cure. Broom finish for traction or trowel for smooth. Cover with plastic for 7 days minimum, lightly mist daily.
- Wait before loading. Foot traffic 24–48 hours. Vehicles 7 days. Heavy equipment 28 days.
Concrete Patio Cost Breakdown
What you actually pay — materials, labor, and finishing options
| Patio Type | Material Cost (sq ft) | Installed Cost (sq ft) | 12x16 Patio Total |
|---|---|---|---|
| Plain broom finish | $2–$4 | $6–$10 | $1,152–$1,920 |
| Stamped concrete | $8–$12 | $12–$18 | $2,304–$3,456 |
| Exposed aggregate | $4–$7 | $8–$14 | $1,536–$2,688 |
| Colored/stained | $4–$8 | $8–$15 | $1,536–$2,880 |
Patio Preparation — What to Do Before You Pour
The prep work determines whether your patio lasts 5 years or 50 years
- Excavate 8–10 inches below finished grade. You need 4 inches of gravel base plus 4 inches of concrete. In freeze-thaw climates, use 6 inches of gravel to improve drainage and reduce frost heaving.
- Compact the subgrade. Rent a plate compactor ($60–80/day) and compact the soil in 2-inch lifts. Soft or loose soil causes settling cracks. This is the most skipped step and the most important one.
- Install 4 inches of compacted gravel base. Use crushed stone (not pea gravel) for stability. Compact it in 2-inch lifts. This base drains water away from the concrete and prevents frost heave.
- Build your forms 4 inches above the gravel. Use 2×4 lumber staked every 2 feet. Slope forms away from the house at 1/8 inch per foot for drainage (a 12-foot patio drops 1.5 inches toward the yard edge).
- Place control joints every 8–10 feet. Concrete shrinks as it cures. Control joints give it a place to crack in a straight line instead of randomly. Place them at 1/4 of the slab thickness deep.
- Add wire mesh or rebar for slabs over 200 sq ft. 6×6 welded wire mesh or #3 rebar on 18-inch centers, elevated 1.5 inches off the base with wire chairs. This won't prevent cracking but keeps cracks tight if they occur.
🚛 Truck Payload Reality Check
Concrete weighs 4,000 lbs per cubic yard. Here is what your truck can legally carry.
| 2026 Truck | Max Payload | Concrete Capacity | Bag Capacity (80lb) |
|---|---|---|---|
| Toyota Tacoma (standard) | 1,521 lbs | ~0.38 cu yd | ~18 bags |
| Toyota Tacoma (i-FORCE MAX) | 1,705 lbs | ~0.42 cu yd | ~21 bags |
| Ford F-150 (PowerBoost Hybrid) | 1,740 lbs | ~0.43 cu yd | ~21 bags |
| Ford F-150 (5.0L V8) | 2,235 lbs | ~0.55 cu yd | ~27 bags |
| Ford F-150 (3.5L EcoBoost) | 2,440 lbs | ~0.61 cu yd | ~30 bags |
| 3/4-ton (F-250, Silverado 2500) | 3,500+ lbs | ~0.87 cu yd | ~43 bags |
*Payload values from 2026 manufacturer specs. Your actual payload is on the door-jamb sticker. Add accessories (toolbox, bedliner) and that number drops 100-300 lbs. A driver and passenger count against payload too.
If your project needs more than 1 cubic yard (4,000 lbs), pickup-truck delivery requires multiple trips. For 2+ cubic yards, ready-mix delivery is almost always cheaper than the gas, time, and suspension wear of multiple bag runs. Most ready-mix trucks deliver 8-10 yards in one trip.
Concrete Slab FAQ
Common questions about calculating and pouring concrete slabs