Yards, bags, rebar, and cost for any shape
2.61 cu yd
70.4 cu ft, 1.99 m³, about 10,560 lb, with 10% waste
118 bags of 80 lb or 157 bags of 60 lb
Bags about $767 vs ready-mix about $629 for 2.75 yd delivered with a short-load fee. Ready-mix wins; the break-even sits near 1 cubic yard.
Add shape
Layers
Selected shape
Select a shape to edit its size, snap it to others, or weld it into one slab.
Arrows nudge · ⌫ delete · ⌘C / ⌘V copy & paste
Furniture and foot traffic. Wire mesh keeps it flat.
Vapor barrier
6-mil poly under interior / enclosed slabs
Include tool rental in total
Add advisory rental/buy estimates to the grand total
Extra concrete for spillage and uneven subgrade. 10% is typical.
Concrete
1.96 yd³
Footprint
144 ft²
Perimeter
48 ft
Ready-mix concrete (3000 psi)
2 cu yd · Ordered by the cubic yard, delivered. Short-load fees apply under ~5 yd.
Alt: Bagged: 88 x 80 lb bags
$330
Compactable gravel base (4")
2.5 tons · 1.78 cu yd of crushed stone / road base, compacted in lifts.
Alt: Recycled concrete aggregate (often cheaper by the ton)
$88
Welded wire mesh (6x6 W1.4)
7 sheets · Flat sheets lay flatter than rolled mesh. Overlap one square.
Alt: Rebar #3 grid (see rebar option)
$63
Mesh chairs / raisers
12 each · Keep mesh off the subgrade, in the slab's middle.
$4
Form boards (2x4)
7 8 ft boards · ~48 linear ft of edge form around the slab.
Alt: Reusable metal forms (rent) for large/curved pours
$42
Form stakes
28 each · One every ~2 ft plus corners. Wood or steel.
$49
Form screws
1 box · Screws (not nails) make stripping forms painless.
$9
Expansion / isolation strip
2 8 ft strips · Where the slab meets a house, footing, or existing slab.
$10
From US average prices — click any price to match a local quote. Excludes delivery, permits, and labor.
Rental prices show only for specialty gear — skip them if you already own it.
Order date, form-up, pour day, and a cure checklist with reminders, plus your materials list on your phone at the supply yard, about $595 in materials at the prices you set.
| Thickness | Cubic yards | 80 lb bags | 60 lb bags |
|---|---|---|---|
| 4 in | 1.23 | 56 | 75 |
| 5 in | 1.54 | 70 | 93 |
| 6 in | 1.85 | 84 | 112 |
| Slab | Cubic yards | 80 lb bags | 60 lb bags |
|---|---|---|---|
| 10 x 10 ft | 1.36 | 62 | 82 |
| 12 x 12 ft | 1.96 | 88 | 118 |
| 20 x 20 ft | 5.43 | 245 | 326 |
| 24 x 24 ft | 7.82 | 352 | 470 |
A monolithic (thickened-edge) slab turns the outer 12 in or so of the slab into a footing, typically 12 in deep and 12 in wide at the bottom, so the floor and footing go in with one truck. Turn on Thickened edge in the quick estimate to add the perimeter beam. For separate wall footings, use the concrete footing calculator.
| 24 x 24 ft garage, 4 in slab | Cubic yards with 10% waste | 80 lb bags |
|---|---|---|
| Flat slab | 7.82 | 352 |
| With 12 x 12 in thickened edge | 10.32 | 465 |
Pouring steps up to your slab? The concrete stairs calculator handles landings and a form cut list. Columns and piers go in the concrete column calculator. Mixing bags by hand? See the concrete mix calculator. Gravel for the base comes from the gravel calculator, and the concrete cheat sheet covers pour day. For any other shape, the concrete calculator does footings, walls, curbs and post holes. Maintaining your slab once it cures? The driveway repair and sealing guide covers crack filling and sealer.
Curing calculator with walk and drive-on dates, strength chart by temperature, mix ratios by PSI, bags per yard, control joints and weather rules
Visual reference illustrating common mortar joints and weather resistance advice
Block selection, base preparation, drainage requirements, and height limitations