How to Estimate Concrete by the Yard (and Bags)
Geometry first, shopping list second
Free Calculator Hub Editorial Team
8 min read
How to Estimate Concrete by the Yard (and Bags)
Concrete estimating is mostly unit discipline. Miss the inch-to-foot conversion and every later step is wrong. Get the prism volume right, then decide whether bags or a truck make sense.
The 27 Rule
Cubic feet ÷ 27 = cubic yards. Ready-mix is sold in yards; bag projects still start from the same volume so you can compare options honestly.
Waste Before You Buy
Apply waste to volume, not after you have already rounded bags down. Short pours are expensive; leftover bags are cheaper than a cold joint.
Key Takeaways
- Convert thickness inches to feet before multiplying
- Divide cubic feet by 27 for yards
- Add waste, then divide by bag yield and round up
- Large volumes usually belong on a ready-mix ticket