Concrete Bag Calculator
Your estimate
- 40 lb bags
- 122
- Concrete (with waste)
- 1.36 yd³36.7 ft³ · 1.04 m³
Every bag size side by side, so you can pick the one that is cheapest or easiest to carry.
Updated 2026-10-20 · Based on: bag yields printed by concrete-mix makers (0.30–0.60 ft³ per bag) and a 1.54 dry-volume factor.
How to use the Concrete Bag Calculator
- Choose Dimensions to type length, width and depth, or Volume if you already know the cubic yards or m³.
- Keep 10 % extra for waste.
- Compare the number of bags for each size and the price per bag at your store.
Formula
Bags = volume × 133 lb/ft³ ÷ bag weight. An 80 lb bag yields about 0.60 ft³, a 60 lb bag 0.45 ft³, a 40 lb bag 0.30 ft³.
Metric bags: volume × 2,130 kg/m³ ÷ bag weight (25, 30 or 40 kg).
Worked example
With the values preset in the calculator above: (Dimensions)
- Length
- 10 ft
- Width
- 10 ft
- Thickness
- 4 in
- Extra for waste
- 10 %
- 80 lb bags
- 61
- Concrete (with waste)
- 1.36 yd³ (36.7 ft³)
How many bags of concrete in a yard?
One cubic yard (27 ft³) takes 45 bags of 80 lb, 60 bags of 60 lb or 90 bags of 40 lb concrete. One cubic metre takes 86 bags of 25 kg.
Bags per volume
| Volume | 80 lb bags | 60 lb bags |
|---|---|---|
| 0.25 | 12 | 15 |
| 0.5 | 23 | 30 |
| 1 | 45 | 60 |
| 1.5 | 68 | 90 |
| 2 | 90 | 120 |
| 3 | 135 | 180 |
Related guides
Frequently asked questions
How many 60 lb bags of concrete do I need?
Divide the cubic feet by 0.45. For one cubic yard that is 60 bags; for half a yard 30.
Are 80 lb or 60 lb bags better?
80 lb bags cost less per cubic foot and mean fewer bags to open. 60 lb bags are easier to lift and mix by hand — the total volume is the same.
How many bags of concrete for a fence post?
Usually one or two 50 lb bags of fast-setting concrete per post. Use the post hole concrete calculator for your hole size.
More calculators
Estimates only — check quantities with your supplier and local building code before you order.