Buying decision calculator
Ready-mix vs bagged concrete calculator
Use bagged concrete for small repairs, post holes, and remote pours. Compare both around 0.25 to 0.75 cubic yards. Ready-mix is usually the better default as the job approaches 1 cubic yard or more because bag counts, labor, and finish timing become the bigger risk.
Quick answer
| Under 0.25 yd3 | Usually bagged |
|---|---|
| 0.25-0.75 yd3 | Compare bag labor vs short-load fee |
| Around 1 yd3 | Ready-mix often wins on speed and consistency |
| Cost basis | $150/yd3, $5 per 80-lb bag, plus delivery variables |
Bagged vs ready-mix breakpoints
These examples show why the decision changes as volume grows. The order and cost columns include 10% extra material.
| Scenario | Dimensions | Base volume | 80-lb bags | Ready-mix with 10% | Bagged with 10% |
|---|---|---|---|---|---|
| Small repair Bagged concrete is usually simpler. | 3 ft x 3 ft x 4 in | 0.12 yd3 | 5 bags before waste | 0.13 yd3 / $20 | 6 bags / $30 |
| Small pad Bags are practical for one or two people. | 4 ft x 4 ft x 4 in | 0.20 yd3 | 9 bags before waste | 0.22 yd3 / $33 | 10 bags / $50 |
| Utility pad Compare mixer capacity and placement time. | 8 ft x 8 ft x 4 in | 0.80 yd3 | 36 bags before waste | 0.87 yd3 / $131 | 40 bags / $200 |
| 10x10 slab Often the point where ready-mix becomes more practical. | 10 ft x 10 ft x 4 in | 1.24 yd3 | 56 bags before waste | 1.36 yd3 / $204 | 62 bags / $310 |
| Patio slab Ready-mix is usually the better field workflow. | 12 ft x 16 ft x 4 in | 2.38 yd3 | 107 bags before waste | 2.61 yd3 / $392 | 118 bags / $590 |
Interactive calculator
Ready-mix vs bagged calculator
Enter your dimensions, waste, ready-mix price, bag price, delivery fee, and short-load assumptions. The table gives a quick default comparison; the calculator lets you adjust the real job.
Bag counts are rounded up. Check the exact yield on the product label before buying.
How to decide what to buy
The cheaper line item is not always the cheaper job
Bags can look cheaper on material price, but the job may need mixer rental, extra labor, more time, and a higher risk of cold joints or uneven finish.
Short-load fees matter on small ready-mix orders
A supplier may charge delivery, minimum order, or short-load fees below a full truck. Those fees can make bags attractive for small pads even when bag labor is unpleasant.
Finish quality favors one continuous batch
For visible slabs, driveways, patios, and garage floors, placement speed and consistency often matter more than saving a few dollars on material.
Material checklist
- Cubic yards with waste for ready-mix ordering
- 80-lb, 60-lb, 50-lb, and 40-lb bag counts from the calculator
- Ready-mix delivery, short-load, wait-time, pump, or buggy assumptions
- Mixer rental, labor, wheelbarrows, water access, forms, and finish timing for bags
Cost assumptions
The table uses $150 per cubic yard for ready-mix and $5 per 80-lb bag. It is a planning comparison, not a delivered quote.
- The table uses concrete-only ready-mix and bag material cost so the baseline is easy to compare.
- Add delivery and short-load fees to ready-mix, then add mixer rental and labor time to bagged concrete.
- For post holes and remote sites, bags can be the right choice even if cost per cubic yard is higher.
Common mistakes
- Comparing bag material cost against a fully delivered ready-mix quote.
- Ignoring how long it takes to mix and place dozens of bags.
- Letting early batches stiffen before the slab is fully placed.
- Forgetting washout, truck access, and minimum-order policies for ready-mix.
Formula and methodology
Volume in cubic feet equals length x width x thickness in feet. Cubic yards equal cubic feet / 27. An 80-lb premix bag is estimated at 0.60 cubic feet. Ready-mix order size and bagged cost use a 10% buying allowance for field variation.