Concrete Slab Rebar Grid Count, Lap Splice & Steel Weight Calculator

Size two-way rebar mats (#3, #4, #5, #6) in 20-ft sticks and total pounds.

20-Foot Rebar Sticks Required (With Laps)
62 bars (20 ft)
Total Linear Footage (With 10% Lap) 1,234.2 linear ft
Total Rebar Weight 824.45 lbs
Wire Tie Intersections 437 ties
Inputs
ft
Concrete slab length in feet.
ft
Concrete slab width in feet.
in OC
On-center rebar grid spacing in inches (e.g., 12", 16", or 18" OC).
lb/ft
Weight per linear foot (0.376 #3, 0.668 #4, 1.043 #5, 1.502 #6).
Results & Graph
20-Foot Rebar Sticks Required (With Laps)
62 bars (20 ft)
Total Linear Footage (With 10% Lap)
1,234.2 linear ft
Total Rebar Weight
824.45 lbs
Wire Tie Intersections
437 ties

20-Foot Rebar Sticks Required (With Laps)

Graph 1 • Slab Length Ft Sensitivity Recalculates the domain equation across 50% to 150% of the primary input while holding other parameters constant.
0 bars (20 ft) 49.7 bars (20 ft) 99.4 bars (20 ft) 50%: 32 bars (20 ft) 32 50% 75%: 46 bars (20 ft) 46 75% 100%: 62 bars (20 ft) 62 100% 125%: 78 bars (20 ft) 78 125% 150%: 92 bars (20 ft) 92 150%
Graph 2 • Primary & Supporting Metric Comparison Compares the primary output alongside supporting domain benchmarks.
20-Foot Rebar Sticks Required (With Laps) 62 bars (20 ft) Total Linear Footage (With 10% Lap) 1,234.2 linear ft Total Rebar Weight 824.45 lbs Wire Tie Intersections 437 ties
Graph 3 • Exact Output Table & Units Displays each calculated output in its exact domain unit.
20-Foot Rebar Sticks Required (With Laps)62 bars (20 ft)Total Linear Footage (With 10% Lap)1,234.2 linear ftTotal Rebar Weight824.45 lbsWire Tie Intersections437 ties
Summary: A 30×24 ft two-way mat at 16" OC requires 1234 linear ft (62 sticks of 20 ft) weighing 824 lbs with 437 grid intersections.
Summary: A 30×24 ft two-way mat at 16" OC requires 1234 linear ft (62 sticks of 20 ft) weighing 824 lbs with 437 grid intersections.
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Interactive chart & math engine powered by CalculatorGraph

Formula & Mathematical Methodology: Rebar Grid & Weight Formula

RowsX = floor(Width / Spacing) + 1
RowsY = floor(Length / Spacing) + 1
TotalFeet = (RowsX·Length + RowsY·Width) × LapFactor
RowsX = floor(Width / Spacing) + 1; RowsY = floor(Length / Spacing) + 1; TotalFeet = (RowsX·Length + RowsY·Width) × LapFactor
  • slabLengthFt: Slab Length Ft (ft)
  • slabWidthFt: Slab Width Ft (ft)
  • gridSpacingIn: Grid Spacing In (in OC)
  • rebarWeightLbPerFt: Rebar Weight Lb Per Ft (lb/ft)

Rounding: Physical package counts round up where appropriate; continuous measurements round to 2 decimal places.

Worked Example: Practical Benchmark: Rebar Grid & Weight

Size two-way rebar mats (#3, #4, #5, #6) in 20-ft sticks and total pounds.

  1. Enter your project dimensions, machining speeds, or recipe weights.
  2. Compute the governing equation: RowsX = floor(Width / Spacing) + 1; RowsY = floor(Length / Spacing) + 1; TotalFeet = (RowsX·Length + RowsY·Width) × LapFactor.
  3. Review the primary result, supporting dimensions, and 3 SVG visualizations.
Result: Computes Rebar Grid & Weight via RowsX = floor(Width / Spacing) + 1; RowsY = floor(Length / Spacing) + 1; TotalFeet = (RowsX·Length + RowsY·Width) × LapFactor.

Frequently Asked Questions

How does the Concrete Slab Rebar Grid Count, Lap Splice & Steel Weight Calculator calculate results?

It evaluates RowsX = floor(Width / Spacing) + 1; RowsY = floor(Length / Spacing) + 1; TotalFeet = (RowsX·Length + RowsY·Width) × LapFactor directly in your browser and plots three custom SVG visualizations.

Can I compare different material dimensions or batch sizes side by side?

Yes. Click "Compare (0/3)" in the results toolbar to pin up to 3 scenarios side by side.

Can I print a clean shop or kitchen reference sheet?

Yes. Click the Print button in the results toolbar for a distraction-free worksheet.

Construction & Home · Concrete & Masonry

Concrete Slab Rebar Grid Count, Lap Splice & Steel Weight Calculator: inputs, method, and how to read the result

Size two-way rebar mats (#3, #4, #5, #6) in 20-ft sticks and total pounds.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Slab Length Ft: Concrete slab length in feet.
  • Slab Width Ft: Concrete slab width in feet.
  • Grid Spacing In: On-center rebar grid spacing in inches (e.g., 12", 16", or 18" OC).
  • Rebar Weight Lb Per Ft: Weight per linear foot (0.376 #3, 0.668 #4, 1.043 #5, 1.502 #6).

What the calculation includes

With the default values shown, 20-Foot Rebar Sticks Required (With Laps) is 62 bars (20 ft). The calculation follows Rebar Grid & Weight Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Slab Length Ft from 30 ft to 33 ft changes 20-Foot Rebar Sticks Required (With Laps) from 62 bars (20 ft) to 68 bars (20 ft). This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard North American & metric trade dimensions, Machinery’s Handbook formulas, and culinary weight ratios.
  • Verify local municipal building codes, tool manufacturer limits, and food-safety time/temperature tables before execution.

Scope: Trade, Shop & Culinary Science Reference Standard Check the assumptions and limitations against your situation before relying on the estimate.

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