Concrete Bag Calculator
Enter the dimensions of the pour and pick a bag size: you get the number of bags to buy, rounded up after the waste allowance, using the yield published on the data sheet. The table compares every bag size and gives the mixing water and total weight you will be carrying.
Bags to buy
—
Results are estimates for planning purposes. Verify with your supplier, engineer, or a qualified professional before ordering material or performing work.
Yield, coverage and mixing water by bag size
| Bag | Yield | Bags per yd³ | Covers at 4 in | Starting water | Max water |
|---|---|---|---|---|---|
| 40 lb | 0.30 ft³ | 90 | 0.90 ft² | 3 pt | 4.5 pt |
| 50 lb | 0.375 ft³ | 72 | 1.13 ft² | 3.5 pt | 5.5 pt |
| 60 lb | 0.45 ft³ | 60 | 1.35 ft² | 4 pt | 7 pt |
| 80 lb | 0.60 ft³ | 45 | 1.80 ft² | 6 pt | 9 pt |
| 90 lb | 0.675 ft³ | 40 | 2.03 ft² | 7 pt | 10 pt |
Yields and mixing water: QUIKRETE Concrete Mix No. 1101 data sheet. Coverage at 4 in is the yield divided by 0.333 ft. Sakrete's High-Strength Concrete Mix publishes the same 0.30 ft³ (40 lb) and 0.45 ft³ (60 lb) yields; its 90 lb bag yields 0.66 ft³. Always check the bag in your hand — yield changes with the product.
Buying and mixing notes
- Round up, and buy one spare. Bags are sold whole and a split bag on the tailgate is not a bag of concrete. The count above is already rounded up after the waste allowance.
- Water is a range, not a target. QUIKRETE lists a starting water content and a maximum expected water content per bag — 6 pt starting and 9 pt maximum for an 80 lb bag. Adding water past the maximum drops strength.
- Mixer capacity. Allow at least 1 ft³ of mixer capacity for each 80 lb bag mixed at one time.
- 2 in minimum. Concrete mix is designed for pours 2 in (50 mm) thick or more.
- Past a cubic yard, price the truck. A cubic yard is 45 bags of 80 lb — about 3,600 lb to carry, open and mix by hand. Most crews compare that against a short-load ready-mix delivery.
How it's calculated
- Volume
V (ft³) = length (ft) × width (ft) × thickness (in) / 12- Volume to place
V order = V × (1 + waste % / 100)- Bags
bags = ceiling(V order / yield per bag)Yields for QUIKRETE Concrete Mix No. 1101: 0.30 ft³ (40 lb), 0.375 ft³ (50 lb), 0.45 ft³ (60 lb), 0.60 ft³ (80 lb), 0.675 ft³ (90 lb). Sakrete's High-Strength Concrete Mix publishes 0.30 and 0.45 ft³ for its 40 and 60 lb bags and 0.66 ft³ for its 90 lb bag. Yield varies by product — check the bag.- Mixing water
water = bags × starting water per bag (3 pt at 40 lb, 3.5 pt at 50 lb, 4 pt at 60 lb, 6 pt at 80 lb, 7 pt at 90 lb)The data sheet also gives a maximum expected water content per bag: 4.5, 5.5, 7, 9 and 10 pt. Water beyond the maximum reduces strength.
Frequently asked questions
A cubic yard is 27 cubic feet: 45 bags of 80 lb (0.60 ft³ each), 60 bags of 60 lb, 72 bags of 50 lb, 90 bags of 40 lb, or 40 bags of 90 lb.
An 80 lb bag yields about 0.60 cubic feet. At 4 in thick that covers 1.8 square feet; at 6 in thick, 1.2 square feet; at 2 in thick, 3.6 square feet.
QUIKRETE Concrete Mix lists a starting water content and a maximum: 3 pt (4.5 pt max) for a 40 lb bag, 4 pt (7 pt max) for 60 lb, and 6 pt (9 pt max) for 80 lb. Mix to a stiff, moldable consistency, roughly a 2 to 3 in slump; extra water past the maximum costs strength.
Allow at least 1 cubic foot of mixer capacity for each 80 lb bag mixed at one time, per the QUIKRETE data sheet. A typical 3.5 ft³ portable mixer takes about three 80 lb bags per batch.
The common sizes match: QUIKRETE and Sakrete both publish 0.30 ft³ for a 40 lb bag and 0.45 ft³ for a 60 lb bag. The 90 lb bags differ (0.675 ft³ QUIKRETE, 0.66 ft³ Sakrete), and high-yield lightweight mixes are deliberately different. Read the bag.
Past about a cubic yard the bag count gets heavy — 45 bags of 80 lb is 3,600 lb to carry, open and mix. That is usually the point where crews price a short-load ready-mix delivery instead, minimum load charge included.
Sources & references
- QUIKRETE Concrete Mix No. 1101 — product data sheet (yield per bag, Table 2 mixing water, mixer capacity, 2 in minimum thickness)
- Sakrete High-Strength Concrete Mix — technical data sheet (yield per bag)
- NRMCA TIP 8 — Concrete Yield (why the placed volume exceeds the calculated volume, per ASTM C94)
Content checked against these sources — last reviewed August 27, 2026.