Calculation sources
Where published product assumptions come from—and where measurements, current specifications and on-site judgment remain necessary.
Primary materials and manufacturer references
- QUIKRETE Concrete Mix No. 1101: published dry-bag yield figures, including the 80 lb example of approximately 0.60 ft³. Official product datasheet.
- Sonoco Sonotube forms: nominal versus actual internal diameter, which affects round-form estimates. Manufacturer Sonotube FAQ.
- ARDEX K 15: manufacturer-specific self-leveling underlayment coverage and thickness restrictions. ARDEX K 15 product page.
- CUSTOM LevelQuik RS: coverage, preparation and product instructions vary by product and version. Manufacturer technical datasheet.
Geometry and uncertainty
The volume math uses standard rectangular-prism and cylinder geometry. Field measurements, nonuniform excavation, compaction, bag yield, uneven slab thickness and additional material allowances introduce uncertainty. Results are material-planning estimates, not engineering signoff or supplier guarantees.
For the exact equations and rounding rules, see our calculation methodology.
Information we do not claim to provide
- Verified local construction permit rules or a structural design for your location.
- Real-time delivered concrete prices by ZIP code or a contractor quote.
- A claim that all concrete bags of the same weight have the same yield.
- A single self-leveler thickness, substrate or primer recommendation valid for every brand.
Verified estimating reference figures
Source check: October 23, 2026. These are manufacturer-published planning inputs, not independently certified material performance or endorsements. Our calculators require you to confirm your exact product or enter your own yield.
| Product and manufacturer | Published estimate | How to use it |
|---|---|---|
| QUIKRETE Concrete Mix No. 1101 | 40 lb ≈ 0.30 ft³; 60 lb ≈ 0.45 ft³; 80 lb ≈ 0.60 ft³ | Specific bag yield, not a universal yield for every concrete brand; source sheet |
| Sonoco Sonotube | Actual inside diameter can be up to 1 in greater than nominal | Measure the actual fill diameter; cylinder volume changes with diameter squared; manufacturer FAQ |
| ARDEX K 15, 55 lb | 30 ft² per bag at 1/4 in | Specific 2026-04-02 technical data; thickness and primer rules depend on application; 2026 technical sheet |
| CUSTOM LevelQuik RS, 50 lb | 23–24 ft² per bag at 1/4 in | Separate product; listed for comparison only, not an active preset in our calculator; TDS-108 |
These area and cubic-foot figures apply to different products and measurement methods. Do not transfer a self-leveling underlayment coverage number into an ordinary concrete bag calculator.