Soil Backfill Calculator with Compaction Factor
Calculate the exact amount of soil needed for your backfill project, accounting for compaction requirements.
How to Use This Calculator
- Enter the length and width of your area in feet
- Enter the desired depth of backfill in inches
- Adjust the compaction factor based on your soil type
- Click “Calculate” to get precise soil requirements
Compaction Factor Guide
- 10-20%: Loose, sandy soil with minimal compaction
- 20-30%: Typical for most backfill projects
- 30-40%: Heavy clay soils or high compaction requirements
Frequently Asked Questions
What is a compaction factor in soil backfill?
The compaction factor accounts for the reduction in soil volume that occurs when it’s compacted. When you excavate soil, it becomes loose and takes up more space. When you put it back, you need extra soil to account for this volume difference after compaction.
How do I determine the right compaction factor?
The compaction factor depends on your soil type and compaction method. Sandy soils typically require 10-20%, loamy soils 20-30%, and clay soils 30-40%. If you’re using mechanical compaction equipment, you might need a higher factor than hand tamping.
Why is my calculated soil amount higher than expected?
This calculator accounts for the fact that excavated soil expands and won’t fit back in the same space without additional material. The compaction factor ensures you have enough soil to achieve proper density after backfilling.