Calculate how much concrete you need in cubic yards and bags for slabs, driveways, sidewalks, and fence posts.
Don't know your area? Measure it with LotSite for free →
Cubic yards and 80-lb bags needed for a 4-inch slab.
| Area | Cu Yards | 80-lb Bags | Bag Cost | Ready-Mix |
|---|---|---|---|---|
| 50 sq ft | 0.6 | 28 | $196 | $93 |
| 100 sq ft | 1.2 | 56 | $392 | $185 |
| 200 sq ft | 2.5 | 112 | $784 | $370 |
| 400 sq ft | 4.9 | 223 | $1,561 | $741 |
| 600 sq ft | 7.4 | 334 | $2,338 | $1,111 |
| 1,000 sq ft | 12.3 | 556 | $3,892 | $1,852 |
The most important step in any concrete project is accurate measurement. Ordering too little means a cold joint (where fresh concrete meets hardened concrete), which creates a structural weakness. Ordering too much wastes money. Add 5 to 10 percent to your calculated volume for waste and spillage.
For small projects (under 1 cubic yard), bagged concrete mix is practical. Just add water and mix in a wheelbarrow or mixer. For anything larger, order ready-mix delivery. Most ready-mix companies have a minimum order of 1 cubic yard and charge short-load fees for small deliveries.
Use LotSite to measure your project area precisely. View your driveway, patio, or walkway area on satellite imagery and get exact square footage, especially useful for irregularly shaped areas.
Enter your address and measure the area for your concrete pour on satellite imagery.
Also check out our paver calculator and gravel calculator