How Bag Yields Work
QUIKRETE publishes specific yield data for each bag size: a 60 lb bag yields 0.45 cubic feet of mixed concrete; an 80 lb bag yields 0.60 cubic feet. These figures are for standard concrete mix (QUIKRETE #1101) and are consistent across the major brands — Sakrete and Rapid Set publish nearly identical yields.
This calculator divides your project volume by those yields and rounds up to the next whole bag. You'll always end up with a small amount of leftover on the final bag — that's by design. Running short mid-pour is far worse than having half a bag left over.
60 lb vs 80 lb Bags: Which to Choose
- 60 lb bags — 0.45 cu ft yield. Lighter and easier to handle, especially for solo work. One person can mix these by hand in a wheelbarrow without straining. Good choice for post holes, small footings, and any project where you're mixing manually.
- 80 lb bags — 0.60 cu ft yield. More concrete per bag, slightly cheaper per cubic foot. The standard choice for larger projects where you're using a rented electric mixer. Heavy to carry if you're doing multiple bags up steps or across a long distance.
- 40 lb bags (high-strength) — 0.30 cu ft yield. Used for repairs and small patching jobs. Not cost-effective for new pours — the price per cubic foot is significantly higher than standard bags.
- Fast-setting mixes — Available in 50 lb bags (QUIKRETE Fast-Setting Concrete: 0.375 cu ft). Used for setting posts without mixing — pour dry into the hole, add water, done in 20–40 minutes. Not suitable for slabs or footings requiring standard curing.
When to call for ready-mix: once you're past 50 bags of 80 lb mix — about 30 cubic feet or just over 1 cubic yard — ready-mix is almost always cheaper per cubic foot and far less labour-intensive.
Need a different shape? The full Concrete Calculator covers slabs, footings, round columns, and post holes in one place.