Mix bag sizes and still get the right count.
⚙️Calculation Parameters
📊Calculated Output
How Mixed Bag Size Calculator Works?
To combine bag sizes, the Mixed Bag Size Calculator subtracts the yield of the bags you choose first and fills the rest with a second size. The process takes 4 steps.
Enter the job volume
Type the tube size and count, or a volume in cubic feet (ft³).
Fix the first bag size
Type how many bags of one size you have or want, such as 8 bags of 80 lb.
Fill with a second size
The calculator divides the remaining volume by the second bag yield, such as 0.45 ft³ for 60 lb, and rounds up.
Check the total
The tool lists the combined yield, the surplus and the total weight.
Mixed Bag Size Calculator Formula
The Mixed Bag Size Calculator adds the yields of each bag group.
Combined yield
V_bags = Σ (nᵢ × Yᵢ)nᵢ bags of yield Yᵢ.
Fill with size 2
n₂ = ⌈(V − n₁ × Y₁) ÷ Y₂⌉Second size covers the remainder.
Surplus
S = V_bags − VExtra concrete after rounding.
Worked example: 4 tubes at 12 in × 48 in, 12 bags of 80 lb on hand
- V = 12.57 ft³; 12 × 0.60 = 7.20 ft³ covered
- Remainder = 5.37 ft³ → ⌈5.37 ÷ 0.45⌉ = 12 bags of 60 lb
- Total yield = 12.60 ft³, surplus 0.03 ft³
Mixed Bag Size Calculator Conversion Table
The mixed bag conversion table shows 6 ways to fill 4 tubes at 12 in × 48 in (12.57 ft³) with 80 lb and 60 lb bags.
| 80 lb bags | 60 lb bags | Total yield ft³ | Surplus ft³ | Total lb |
|---|---|---|---|---|
| 0 | 28 | 12.60 | 0.03 | 1680 |
| 4 | 23 | 12.75 | 0.18 | 1700 |
| 8 | 18 | 12.90 | 0.33 | 1720 |
| 12 | 12 | 12.60 | 0.03 | 1680 |
| 16 | 7 | 12.75 | 0.18 | 1700 |
| 20 | 2 | 12.90 | 0.33 | 1720 |
Combinations with the smallest surplus waste the least concrete.
What is Mixed Bag Size Calculator?
A Mixed Bag Size Calculator is a bag planner that combines 2 or more bag sizes, each with its own yield, to cover one concrete volume.
Store stock runs out, leftover bags sit in the garage, or one crew member lifts lighter bags. A job of 4 deck piers can use 12 bags of 80 lb plus 12 bags of 60 lb. The calculator adds each yield correctly, so a 60 lb bag never counts as a full 80 lb bag.
The tool reports the surplus for each combination and picks out the one with the least leftover.
What are the uses of Mixed Bag Size Calculator?
There are 4 main uses of the Mixed Bag Size Calculator.
Store shortages
Buyers fill a gap when the store lacks enough 80 lb bags.
Leftover stock
Owners use mixed leftover bags first.
Lifting mix
Crews split heavy and light bags among workers.
Cost tuning
Estimators pick the cheapest mix of sizes.
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