Square Yardage Calculator for Dirt: Topsoil, Fill Dirt & Volume Guide

Earthwork & Soils September 4, 2026 · 9 min read

Grading a sloped lawn, building raised garden beds, or filling low sinkholes after removing a tree? Soil and earth are sold in bulk by the cubic yard, but property owners measure the target area in square yards or square feet.

Unlike stone or concrete, dirt has one tricky physical property: settling. Freshly fluffed soil delivered by a dump truck contains millions of micro-air pockets. Once it rains, that dirt compresses by 15% to 20%. If you order the exact calculated theoretical volume, your finished lawn will sink several inches below your sidewalks. This guide explains how to convert square yardage into true delivered cubic yards.

Topsoil vs. Fill Dirt: Which One Do You Need?

Ordering the wrong soil type can ruin a lawn project:

Soil Profile

Topsoil vs. Fill Dirt Layers

Topsoil Layer (2" – 6") Nutrient-rich, organic matter, dark loam Fill Dirt Sub-layer Clay, sand, compactable, zero organic decay
When to Use Each:
  • Topsoil: Lawns, sod prep, flower beds, and garden boxes. Never use deep fill dirt for plants!
  • Fill Dirt: Backfilling retaining walls, filling deep ruts (>6 inches), and grading foundation slopes. Never use topsoil as structural fill because it decomposes and causes sinkholes.

The Dirt Volume Formula

Formula: From Feet to Cubic Yards
Cubic Yards = Length (ft) × Width (ft) × Depth (in) ÷ 324
Formula: From Square Yards to Cubic Yards
Cubic Yards = Square Yards × Depth (in) ÷ 36

Accounting for 15% Settling: Multiply the raw cubic yards by 1.15.

Interactive Dirt & Topsoil Estimator

Interactive Feature

Interactive Soil, Yardage & Truckload Tool

Delivered Dirt Volume
7.10 Cubic Yards
Includes 15% settling buffer (6.17 base yd³)
Surface Area: 500 sq ft (55.6 yd²)
Dump Truck Loads: 1 Single-Axle Truck

Standard Depth Guidelines for Earthwork

Quick Dirt Yardage Reference Table

Area Size Depth Cubic Yards (Base) With 15% Settling Truck Size
100 sq ft (11.1 yd²)3 inches0.93 yd³1.07 yd³Pickup truck bed
250 sq ft (27.8 yd²)4 inches3.09 yd³3.55 yd³1 Small dump truck
500 sq ft (55.6 yd²)4 inches6.17 yd³7.10 yd³1 Standard dump truck
1,000 sq ft (111 yd²)4 inches12.35 yd³14.20 yd³1 Tri-axle dump truck
2,500 sq ft (278 yd²)6 inches46.30 yd³53.24 yd³3 to 4 Large dump trucks

Explore More Dirt & Earthwork Calculators

Frequently Asked Questions

Topsoil contains organic matter and nutrients for grass and plants. Fill dirt is deep subsoil free of organic decay, used for building structural grade and backfilling.

Multiply square yards by depth in inches and divide by 36. For example: 50 sq yd at 3 inches deep = (50 × 3) ÷ 36 = 4.17 cubic yards.

Loose topsoil and compost settle by 15% to 20% after watering and rain. Always add 15% extra to prevent sunken spots.

A standard single-axle dump truck carries 5 to 7 cubic yards. A larger commercial tandem truck carries 10 to 14 cubic yards.

Since 1 cubic yard equals 27 cubic feet, you need 27 one-cubic-foot bags (or 36 three-quarter-cubic-foot bags) to make 1 cubic yard.