Concrete Bag Calculator – Compare Bags & Prices

That depends on the exact bag product. A commonly published approximate yield for a QUIKRETE 80 lb Concrete Mix bag is 0.60 ft³. Because one cubic yard is 27 ft³, 27 ÷ 0.60 = 45 bags before any allowance. Other product formulas can have different yields; always enter the actual yield on the bag or technical data sheet for the product you intend to buy.

Worked example: For a 10 ft × 10 ft × 4 in slab, net concrete is 33.33 ft³. Add 5% allowance: 35 ft³. Using an illustrative 0.60 ft³ yield per 80 lb bag, 35 ÷ 0.60 = 58.33, so 59 whole bags are needed. This is a quantity example, not a substitute for the product data sheet.

Weight is the packaged dry mass, not finished mixed-concrete volume. Different mixes, lightweight products, aggregate gradations, special mortars and cement-only products can produce different yields per pound or kilogram. Manufacturer-stated mixed yield is therefore the defensible basis for whole-bag purchasing. Bag weight is still useful for handling and transport totals.

Concrete bags normally must be purchased as whole bags. If the calculated requirement is 12.01 bags, buying 12 would leave the job short under the selected yield. The calculator returns 13 whole bags and separately shows surplus mixed volume caused by rounding. That surplus is not permission to pour concrete where no designed volume exists.

Select a round section and measure the actual hole diameter and concrete-filled depth. Enter quantity for identical holes. If a solid post occupies part of the hole and should be subtracted, use a real, correctly measured deduction or verify the concrete displacement separately. Excavated holes are often uneven; site dimensions may differ from nominal drill-bit sizes.

Select the matching bag weight and metric weight unit, but enter the actual finished concrete yield in litres or cubic metres from its packaging. Do not infer a universal yield from 25 kg or 50 kg alone. You can measure the project in feet, centimetres or metres independently of the weight unit.

Yes. First, the calculator determines net concrete volume from all complete project sections, then applies the allowance percentage you enter. It divides that required volume by bag yield and rounds upward to whole bags. You should not independently apply the same percentage again to the displayed bag count unless your real job requires an additional, separately justified allowance.

No. Premixed concrete usually contains a pre-proportioned cementitious binder and aggregates; you normally add water as directed by the manufacturer. A cement bag contains cement, and you need specified sand, coarse aggregate and water to make concrete. Use the separate Concrete Mix Calculator when you plan to buy the ingredients individually.

Enter the current retail price per bag and the actual product bag weight. The tool multiplies the whole-bag count by your price and shows the total dry bag weight. These exclude pallets, vehicle capacity limits, unloading, local tax, transport and additional equipment unless you account for them separately. Confirm store pack sizes and stock availability before travel.

No. Buying by sticker price alone ignores each product’s yield. Suppose a job requires 35 ft³ after allowance. A 40 lb product yielding 0.30 ft³ needs 117 bags; at $4.20 each, the materials cost $491.40. A 60 lb product yielding 0.45 ft³ needs 78 bags; at $6 each, materials cost $468. An 80 lb product yielding 0.60 ft³ needs 59 bags; at $7.50 each, materials cost $442.50. The larger bag has the lowest total bag-material cost in this example, even though its sticker price is highest.

The tool adds any entered sales tax and fixed bag delivery/handling to each option. These prices are hypothetical; confirm your own product yields, required strength/suitability, availability, bag handling, labor and supplier quote before purchasing.