Backfill Calculator
Calculate backfill volume from trench length, width, and backfill depth. Optionally subtract a circular pipe so the takeoff is net material, not the full trench prism.
Enter your values, then press Calculate.
How to calculate
Enter trench length, excavated width, and the depth of backfill (often from pipe top to grade, or full depth minus bedding). Enter pipe outside diameter to deduct displacement, or leave it at zero for a gross prism. Add waste for compaction.
Formula
Gross ft³ = length × width × depth. Pipe ft³ = π × (OD/2)² × length. Net ft³ = max(gross − pipe, 0). Cubic yards = ft³ ÷ 27. Waste multiplies net yards for compaction and over-excavation.
Common use cases
- Utility trench backfill takeoffs
- Net yards after a pipe is in the trench
- Comparing native vs import backfill
- Checking haul tickets against a cut
Worked example
Example: Gross prism without pipe
1. Gross trench prism
100 × 2 × 3 = 600 ft³
2. Pipe displacement
π × (0 / 2)² × 100 = 0 ft³
3. Net cubic yards
600 ft³ ÷ 27 = 22.2222 yd³
Related calculators
- Trench Excavation CalculatorConvert trench length, width, and depth into cubic yards of excavation.
- Trench Spoils CalculatorConvert bank trench yards to loose spoils and truckloads using a swell factor.
- Bedding CalculatorEstimate pipe bedding cubic yards from length, width, and depth.
- Truckload EstimatorConvert cubic yards into truckloads using a real truck capacity.
- Pipe Volume CalculatorCalculate internal volume of a circular pipe in cubic feet and gallons.
FAQ
Should depth be full trench depth?
Use the thickness you will actually backfill. If bedding is already placed, measure from the top of bedding or pipe to finished grade, not the original trench bottom.
Why subtract pipe volume?
A pipe occupies space that native or import backfill will not fill. Leave OD at zero if you want a conservative gross prism.
Disclaimer
These calculators are estimating tools for planning and field checks. They are not a substitute for approved plans, specifications, licensed professional engineering, or governing standards. Confirm densities, waste factors, and yields with your supplier and project documents.