What this calculator does
This tool turns your measurements into a consistent planning estimate you can review before pricing or starting work. It is useful during early takeoffs, option comparisons, and on-site checks where transparent math matters.
How the calculation works
Formula
Volume = length × width × depth × quantity. Planned volume = volume × (1 + waste%).Worked example
A 10 × 12 ft slab, 4 in thick, is 40 ft³ or 1.48 yd³ before waste.
How to measure
- 01Measure the finished inside dimensions of the pour.
- 02Take several depth readings where the base is uneven.
Common mistakes to avoid
- Entering inches as feet
- Forgetting repeated footings
- Ordering exactly the theoretical volume
Limits of this estimate
Bag yields are typical planning values—40 lb: 0.30 ft³, 60 lb: 0.45 ft³, 80 lb: 0.60 ft³. Product yield and site conditions vary.
Frequently asked questions
How much waste should I add?
Five to ten percent is a common planning range, but base accuracy and access can change it.
Does this cover irregular shapes?
Split the shape into rectangles and calculate each section.