Concrete Guides
Plain-English guides with worked examples that use the same math as our calculators. Start with how much concrete you need, then follow the topics through to curing.
Estimating quantity
- How much concrete do I needThe formula, units, waste and worked examples.
- How to calculate cubic yardsConvert feet, inches, meters and areas to yd³.
- Bags of concrete per yardBag counts for 40, 50, 60 and 80 lb mix.
- Slab thickness guideWhat 3, 4, 5 and 6 inches are used for.
- Concrete weight per yardAbout 4,050 lb per yard at 150 lb/ft³.
Buying and cost
Mix, strength and materials
Building and finishing
- How to pour a slabFrom excavation to curing, in order.
- Formwork basicsLumber sizes, stakes, bracing and curves.
- Rebar spacing and sizeBar sizes, grids, chairs and wire mesh.
- Control jointsSpacing, depth and timing for saw cuts.
- Concrete curing timeWhen you can walk, drive and build on it.
- Concrete for fence postsHole size, depth and bags per post.
Reference
Estimate only. Results depend on the numbers you enter, ground conditions and your supplier. For structural work consult a licensed engineer and follow local codes. Brand names such as Quikrete and Sakrete are used only to cite published product data. This site is not affiliated with any brand.