★ CONSTRUCTION · CONCRETE · MATERIALS
A 20 ft by 12 ft slab needs 2 sheets of 6x6 W1.4 mesh weighing 67.2 lb at $96.00 — and the same slab in heavier W2.9 mesh still needs 2 sheets, just twice the weight. Pick your slab size, mesh type, and price and the calculator counts sheets, rolls, weight, and cost, in feet or metres.
A 20 ft by 12 ft slab (240 sq ft) needs 2 sheets of 6x6 W1.4 mesh at $48 a sheet: 67.2 lb of mesh for $96.00. Enter your slab size, mesh type, and price and the calculator counts sheets, rolls, weight, and cost.
Welded wire reinforcing mesh (ASTM A1064) comes in sheets and rolls. The type code gives the grid spacing and the wire size: 6x6 means the wires are 6 inches apart both ways, and W1.4, W2.9, or W4.0 is the wire area in hundredths of a square inch — bigger W means thicker wire and heavier mesh. These weights are standard published values per manufacturer tables.
| Mesh type | Grid × wire | Weight per 100 sq ft | Weight per sheet |
|---|---|---|---|
| 6x6 W1.4/W1.4 | 6 in × 10 ga wire | 21 lb | 33.6 lb |
| 6x6 W2.9/W2.9 | 6 in × 6 ga wire | 42 lb | 67.2 lb |
| 6x6 W4.0/W4.0 | 6 in × 4 ga wire | 58 lb | 92.8 lb |
| Form | Size | Area | Effective coverage (with 6 in overlap) |
|---|---|---|---|
| Standard sheet | 8 ft × 20 ft | 160 sq ft | 146.25 sq ft |
| Standard roll | 5 ft × 150 ft | 750 sq ft | 672.75 sq ft |
Three steps. First, the slab area: length × width, converted to square feet if you entered metres (1 sq m = 10.7639 sq ft). Second, the sheet count: divide the area by the effective coverage per sheet — 146.25 sq ft, which is the 8 ft × 20 ft sheet minus a 6-inch overlap on each side, or 7.5 ft × 19.5 ft — and round up, because you cannot buy part of a sheet. Third, weight and cost: each sheet weighs 160 sq ft × the mesh weight per square foot (21 lb per 100 sq ft is 0.21 lb per sq ft, so a W1.4 sheet is 33.6 lb), and cost is sheets × price per sheet. The roll option uses the same steps with the roll's effective coverage of 672.75 sq ft and a full-roll weight of 750 sq ft × the weight per square foot.
Setup: slab 20 ft × 12 ft; mesh 6x6 W1.4/W1.4 (10 ga); price $48.00 per sheet.
Line 1 — slab area. 20 × 12 = 240.0 sq ft.
Line 2 — sheets needed. 240 / 146.25 = 1.64, rounded up = 2 sheets.
Line 3 — weight per sheet. 160 × 0.21 = 33.6 lb.
Line 4 — total weight. 2 × 33.6 = 67.2 lb (30.48 kg).
Line 5 — cost. 2 × $48.00 = $96.00.
Line 6 — roll option. 240 / 672.75 = 0.36, rounded up = 1 roll; full-roll weight 750 × 0.21 = 157.5 lb, but only 240 × 0.21 = 50.4 lb of mesh is actually used.
10x10 ft patio, 100 sq ft: 100 / 146.25 = 0.68, rounded up = 1 sheet, 33.6 lb, $48.00. One sheet covers a small patio with room to spare.
40x20 ft slab, 800 sq ft: 800 / 146.25 = 5.47, rounded up = 6 sheets, 201.6 lb, $288.00. A big slab needs six sheets and a helper to carry them.
Same 20x12 ft slab in W2.9 at $62 a sheet: still 2 sheets, but each weighs 67.2 lb, so the total is 134.4 lb and the cost is $124.00. Thicker mesh doubles the weight and the handling, not the sheet count.
Roll option for the default slab: 1 roll covers it, with a full-roll weight of 157.5 lb and only 50.4 lb actually used — the rest is offcut. Rolls win on big slabs and lose on small ones.
Metric — 6 m x 4 m: 24 sq m × 10.7639 = 258.3 sq ft, so 2 sheets, 67.2 lb = 30.48 kg. The sheets are still the US 8 ft × 20 ft size; metric users enter metres and get sheet counts from the same sheets.
Reverse — what 5 sheets cover: 5 × 146.25 = 731.25 sq ft — for example a 20 ft × 36.6 ft slab (731.25 / 20 = 36.5625 ft).
Sheet and roll sizes are the standard US sizes: 8 ft × 20 ft sheets (160 sq ft) and 5 ft × 150 ft rolls (750 sq ft). The overlap allowance is 6 inches — one grid — on each side, which is the usual practice for 6-inch mesh; your engineer or local code may call for more on heavy slabs. Weights are nominal per manufacturer tables and vary slightly by producer. Prices vary by region and supplier — the price input is editable, and the default $48 is for W1.4 mesh only. The calculator counts the mesh for the slab area you enter and does not add a spare sheet; on an irregular slab, buy one extra sheet for cuts. Rounding convention: sheets and rolls are always rounded up, weight to 1 decimal, kilograms to 2 decimals, money to cents, all computed from unrounded values.
| Output | Formula | What it means |
|---|---|---|
| Slab area | length × width (× 10.7639 if metres) | 240.0 sq ft at the defaults. |
| Sheets needed | ceil(area / 146.25) | 2 sheets for the default slab. |
| Total weight | sheets × 160 × lb per sq ft | 67.2 lb (30.48 kg). |
| Cost | sheets × price per sheet | $96.00 at $48 a sheet. |
| 10x10 patio | ceil(100 / 146.25) | 1 sheet, 33.6 lb, $48.00. |
| 40x20 slab | ceil(800 / 146.25) | 6 sheets, 201.6 lb, $288.00. |
| W2.9, $62/sheet | same slab, heavier mesh | 2 sheets, 134.4 lb, $124.00. |
| Metric 6x4 m | 24 sq m × 10.7639 | 2 sheets, 67.2 lb = 30.48 kg. |
| 5 sheets cover | 5 × 146.25 | 731.25 sq ft — a 20 × 36.6 ft slab. |
Weights are nominal per manufacturer tables and vary slightly by producer; the 21, 42, and 58 lb per 100 sq ft figures are the standard published values for 6x6 W1.4, W2.9, and W4.0 mesh, and a different producer's sheet can be a pound or two off per sheet. Prices vary by region and supplier — the price input is editable and the $48 default is for W1.4 mesh only; W2.9 and W4.0 cost more per sheet. The 6-inch overlap is the usual practice for 6-inch mesh, but your engineer or local building code may require a larger overlap or a different mesh for structural slabs, driveways carrying heavy vehicles, or slabs on poor soil. Mesh holds cracked concrete together; it does not stop concrete from cracking — control joints do the crack control. Always round sheets up and add one spare sheet for cuts on irregular slabs.
Bright Side Kit. "Concrete Reinforcing Mesh Calculator: Sheets, Weight & Cost" https://brightoolbox.com/concrete-reinforcing-mesh-calculator/ Accessed October 24, 2026.Sheets for small and medium slabs, rolls for big ones. A 10x10 ft patio needs 1 sheet and a 20x12 ft slab needs 2 sheets, while a roll covers 672.75 sq ft after overlap — a roll is one piece to handle instead of many sheets, but on a small slab most of the roll is offcut: the default slab uses 50.4 lb of a 157.5 lb roll.
6 inches — one grid — on each side. That is why a nominal 8 ft × 20 ft sheet only covers 7.5 ft × 19.5 ft = 146.25 sq ft effectively. Your engineer or local code may call for more overlap on heavy or structural slabs, so check before you order.
W1.4 for patios and light slabs, W2.9 or W4.0 for driveways and heavy loads. A driveway carries cars, so the thicker 6-gauge W2.9 or 4-gauge W4.0 wire is the usual pick; a patio carries foot traffic, so the lighter 10-gauge W1.4 is enough. The sheet count is the same either way — only the weight and the price change.
They do different jobs. Mesh is a light steel grid that holds a slab together and is quick to lay over a large area; rebar is individual heavy bars that carry structural loads in beams, footings, and thick slabs. Patios and driveways usually get mesh, structural work usually gets rebar, and some slabs get both.
No — mesh holds cracked concrete together; control joints do the crack control. Concrete shrinks as it cures and will crack somewhere. Control joints give it a planned place to crack, and the mesh keeps the two sides from separating or settling apart. A slab with mesh and no joints still cracks, just in the wrong places.
Yes — the mesh must sit in the middle of the slab, not on the ground. Mesh laid flat on the subgrade ends up at the bottom of the pour, where it does almost nothing. Use mesh chairs, concrete dobies, or bar chairs to hold it at mid-depth while you pour, and pull it up with a hook if it sinks.
Carefully, and only on supported mesh. Walking on unsupported mesh pushes it down to the bottom of the slab, where it stops working. Pour in sections, keep the mesh on its chairs, and use a rake or hook to lift it back to mid-depth as the concrete flows in.
US mesh is sold in feet, so metric users enter metres and get sheet counts from the same 8 ft × 20 ft sheets. A 6 m × 4 m slab is 24 sq m = 258.3 sq ft, which needs 2 sheets weighing 67.2 lb (30.48 kg). If your supplier stocks metric-sized sheets, the same math works with their sheet dimensions.