🧱Concrete Calculator: Cubic Yards & Bags
Pick a slab, footing or round column, add your sizes and get cubic yards plus how many bags to buy.
Your pour
You'll need about
1.36 cubic yards
1.04 m³ · 36.7 cu ft
80 lb bags
62
60 lb bags
82
Cubic metres
1.04
Cubic feet
36.7
Over about 1 cubic yard? A ready-mix truck is usually cheaper (and kinder to your back) than bags.
Popular sizes & projects
How it works
- Slab: length × width × thickness
- Footing: length × width × depth
- Round column: π × (diameter ÷ 2)² × height × number of columns
Convert everything to feet, then cubic yards = cubic feet ÷ 27. Add your waste factor.
Bags: a 60 lb bag makes about 0.45 cu ft and an 80 lb bag makes about 0.60 cu ft.
Worked example
A 10 × 10 ft patio, 4 in thick: 10 × 10 × 0.333 = 33.3 cu ft. Add 10% → 36.7 cu ft = 1.36 cu yd. That's 36.7 ÷ 0.6 = 62 × 80 lb bags or 36.7 ÷ 0.45 = 82 × 60 lb bags.
Questions people ask
4 inches is standard for patios and walkways. Driveways usually need 5–6 inches.
More calculators you might like
Deck Calculator
Work out deck boards, joists, beams, posts, screws and footing concrete for your new deck.
Fence Calculator
Enter your fence length, post spacing, height and gates to get a full shopping list.
Flooring Calculator
Add your rooms, pick your waste factor and see exactly how many boxes of flooring to bring home.
Mulch Calculator
Tell us the size of your bed and how deep you want it — we will do the digging (in numbers).
Email me my results
Pop in your email and keep your numbers handy at the store.
Last updated September 28, 2026. These results are friendly estimates to help you plan — always double-check before buying or making big decisions.