What's the standard rebar spacing for a concrete slab?

For residential slabs, #4 rebar at 12-18 inches is typical. For heavier commercial slabs, #5 at 12 inches. Always check local building codes - our calculator automatically adjusts to minimum spacing requirements based on ACI 318-26 building codes.

Steel Rebar Calculator 2026: How Much Rebar Do I Need?

🏗️ Over 10,000 USA contractors use this tool. Our FREE steel rebar calculator 2026 answers the #1 construction question: "How much rebar do I need?" Get instant estimates for quantity, weight, and cost for footings, slabs, walls, columns, and beams.

🔥 Popular calculations: 20'×20' slab with #4 rebar at 18" spacing → 1,200 linear feet (800 lbs) · #3 rebar price per foot 2026 → $0.16-0.18 · #4 rebar weight per foot → 0.668 lbs.

How This Rebar Calculator Answers "How Much Rebar Do I Need?"

The most common question on construction sites is "how much rebar do I need?" Our steel rebar calculator 2026 provides the answer instantly, using the latest ACI 318-26 building codes and ASTM A615 standards. With over 10,000 monthly users across USA construction projects, it's the most trusted tool for rebar estimation.

📊 2026 Rebar Weight per Foot

#3 Rebar (3/8"): 0.376 lb/ft
#4 Rebar (1/2"): 0.668 lb/ft
#5 Rebar (5/8"): 1.043 lb/ft
#6 Rebar (3/4"): 1.502 lb/ft
#7 Rebar (7/8"): 2.044 lb/ft
#8 Rebar (1"): 2.670 lb/ft

💰 2026 Rebar Price per Foot

#3 Rebar: $0.16-0.18 per foot
#4 Rebar: $0.30-0.33 per foot
#5 Rebar: $0.50-0.55 per foot
#6 Rebar: $0.75-0.83 per foot
#7 Rebar: $1.12-1.22 per foot
#8 Rebar: $1.60-1.74 per foot

📐 Example: 20'×20' Slab Rebar Calculation (May 2026)

#4 rebar at 18" spacing:

Bars in length direction: (20×12÷18)+1 = 14 bars × 20' = 280 linear feet
Bars in width direction: (20×12÷18)+1 = 14 bars × 20' = 280 linear feet
Total rebar needed: 560 linear feet (before waste/laps)
With 10% waste + lap splices: ~650 linear feet
Total weight: 650 ft × 0.668 lb/ft = 434 lbs (0.22 tons)
Total cost at $950/ton: $209 + tie wire ≈ $225

Popular question: "How much rebar do I need for a 20x20 slab?" → Approximately 650 linear feet of #4 rebar (434 lbs).

❓ Frequently Asked Questions About Rebar (May 2026)

How much rebar do I need for my slab?

For a standard 20'×20' slab with #4 rebar at 18" spacing, you'll need approximately 1,200 linear feet of rebar (about 800 lbs or 0.4 tons). The calculator accounts for both directions and includes waste factor. Enter your dimensions above for exact quantities.

How much does rebar cost in 2026?

Current 2026 prices range from $850-1,250 per ton depending on size: #3: $850-950/ton, #4: $900-1,000/ton, #5: $950-1,050/ton, #6: $1,000-1,100/ton. Use our calculator with current prices for accurate estimates.

How do you calculate rebar weight?

Rebar weight is calculated using ASTM A615 standard weights: #3 (0.376 lb/ft), #4 (0.668 lb/ft), #5 (1.043 lb/ft), #6 (1.502 lb/ft), #7 (2.044 lb/ft), #8 (2.670 lb/ft). Our calculator automatically applies these standards.

What size rebar do I need for a footing?

For residential footings, #4 rebar (1/2") is typically sufficient. For heavier loads or commercial projects, #5 (5/8") or #6 (3/4") may be required. Always consult your structural engineer for final specifications.

How much overlap for rebar splices?

Lap splice length is typically 40-50 times the bar diameter. For #4 rebar (1/2"), that's 20" (40×0.5"). For #5 rebar (5/8"), that's 25". Our calculator includes lap splices when checked.

What is #3 rebar price per foot 2026?

#3 rebar price per foot in 2026 ranges from $0.16-0.18, based on $850-950 per ton. At $900/ton, #3 rebar costs approximately $0.17 per linear foot.

⚠️ Construction Disclaimer (Updated May 9, 2026)

Estimates Only: This steel rebar calculator provides estimates based on ACI 318-26 building codes and ASTM A615 standards. Results are for preliminary estimation only and should be verified by a licensed structural engineer for final design.

Last Update: May 9, 2026 | Next Review: August 9, 2026 | Users: 10,000+ contractors

Steel Rebar Calculator 2026: How Much Rebar Do I Need? Quantity, Weight & Cost Estimator

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