Concrete Bag Calculator
How many bags a pour needs, by product and bag size.
Pour
= 96" (8')
= 48" (4')
= 4"
Results update as you typeLive
Concrete Bags · Result
CalculatedBAGS TO BUY
20 bags of Quikrete Concrete Mix No. 1101
- Volume
- 0.43 yd³
- Yield per bag
- 0.6 ft³
- Exact bags
- 19.6
- Waste
- 10%
Waste allowance 10%
SUGGESTED DEFAULTChangeOutput unit defaulted to cubic yards because at least one dimension was entered in imperial units
SUGGESTED DEFAULTReady-mix order increment 0.25 yd³ and minimum 1 yd³ are UI defaults; suppliers differ
SUGGESTED DEFAULTBag yields are the manufacturer's printed approximate figures; cubic-metre yields are derived from them
MFR SPECCode references & assumptions · 3
How this result is supported
- SUGGESTED DEFAULTOutput unit defaulted to cubic yards because at least one dimension was entered in imperial units
- ASSUMPTION
- SUGGESTED DEFAULTReady-mix order increment 0.25 yd³ and minimum 1 yd³ are UI defaults; suppliers differ
- ASSUMPTION
- MFR SPECBag yields are the manufacturer's printed approximate figures; cubic-metre yields are derived from them
- PRIMARY-VERIFIED
What do these evidence labels mean?
- PRIMARY-VERIFIED
- directly supported by one authoritative primary source, quoted with section/page/figure
- CROSS-VERIFIED
- independently supported by two or more appropriate authoritative sources
- DERIVED
- mathematically derived from PRIMARY-VERIFIED values; the derivation is preserved in data and in code
- INTERPRETED
- a source exists but translating it into calculator behaviour required interpretation
- CONVENTION
- recognised trade practice, not a mandatory provision
- ASSUMPTION
- product/design assumption or useful default with no authoritative basis
- UNVERIFIED
- insufficient authoritative evidence
Code references and product data are quoted in the units their source uses.
Reference checks are informational, not compliance determinations.
How concrete bag is calculated
Bag counts come from the yield printed on the product's own data sheet, not from a rounded rule of thumb. That is why the calculator names the product and the yield it used — two 80 lb products can differ, and the difference shows up as whole bags on a small pour.
The count is rounded up, because a part bag is a whole bag when you buy it. The volume before rounding is shown alongside, so you can see how close the last bag was.
Past roughly a cubic yard the mixing time and the number of bags stop being worth it. The calculator does not decide that for you, but it shows the bag count plainly enough that the crossover is visible.
V = length × width × thickness
bags = ceil(V ÷ yield per bag)
Rounded up: a part bag is a whole bag at the till.