Backfill Calculator – Estimate Tons, Volume & Cost

Material	lbs/ft³	kg/m³
Clean Topsoil	90–100	1440–1600
Dry Sand	100–110	1600–1760
Crushed Stone/Gravel	100–115	1600–1840
Dense Road Base	120–135	1920–2160
Wet Clay	110–125	1760–2000

Material	Cost / Ton
Fill Dirt	$10 – $25
Screened Topsoil	$20 – $40
Washed Sand	$25 – $45
Crushed Gravel/Stone	$30 – $60

Trench Size (L×W×D)	Gravel (Tons)
50' × 2' × 3' deep	~15.5 tons
100' × 2' × 3' deep	~31.0 tons
100' × 3' × 4' deep	~62.0 tons

How to Calculate Backfill Material: A Complete Guide

This backfill calculator estimates the total volume in cubic yards (or cubic meters) and total weight in tons needed to fill trenches, foundation walls, retaining wall cavities, and hollow excavations. Simply select your material type, input excavation dimensions, and factor in compaction and waste loss.

      📐 Quick Start: 3 Steps to Calculate Backfill Quantities

      Step 1: Calculate excavation area: Length × Width = Square Footage

      Step 2: Calculate cubic volume: Square Footage × Depth = Cubic Feet

      Step 3: Convert to Yards & Tons: Cubic Feet ÷ 27 = Cubic Yards. Multiply Cubic Feet by Material Density (lbs/ft³) ÷ 2000 = Tons needed.

      Example: A 50 ft trench, 2 ft wide, 3 ft deep = 300 cu ft. In cubic yards: 300 ÷ 27 = 11.11 cu yd. In gravel tons (105 lbs/ft³): 300 × 105 = 31,500 lbs ÷ 2000 = 15.75 tons. Add 10% compaction = 17.3 tons total.

🔄 Backfill Material Types Compared

Material	Drainage	Compaction Ease	Best Used For
Crushed Stone / Gravel	Excellent	Very High (Self-consolidating)	Retaining walls, French drains, utility pipes
Sand	Good	High (when moist)	Pipe bedding, electrical conduit backfill
Common Dirt / Clean Soil	Poor to Moderate	Moderate (Requires lifts)	General grading, deep non-structural filling

Our recommendation: For structural foundations or behind retaining walls, clear angular aggregate or crushed stone provides superior drainage and long-term stability against settlement.

Understanding Soil Compaction Factors

When soil or aggregate is excavated, it expands (loose volume). When backfilled and mechanically tamped with a plate compactor or roller, it compresses (compacted volume). You must order more loose material than the geometric void space to ensure proper fill levels.

Material State	Volume Change Factor	Compaction Allowance to Add
Coarse Gravel / Aggregate	Minimal shrinkage	5% – 10%
Sand Fill	Slight settlement	10% – 12%
Common Excavated Dirt	Moderate compaction	15% – 20%
Clay Soil	High swell/shrinkage	20% – 25%

Backfill Volume & Weight Calculator

📊 Results

📋 Quick Answer: 1 Cubic Yard Covers

📊 Density Reference Table

💰 Average Material Cost

🚧 Trench Estimation Guide

How to Calculate Backfill Material: A Complete Guide

🔄 Backfill Material Types Compared

Understanding Soil Compaction Factors