How Do You Calculate Cubic Yards? A Simple Guide

Published 2026-01-18

To calculate cubic yards, multiply length × width × depth in feet and divide by 27. If your depth is in inches, divide it by 12 first. A 10 × 12 ft area at 4 inches deep is about 1.48 cubic yards.

Bulk materials — topsoil, gravel, mulch, concrete — are sold by the cubic yard, but you almost never measure a project in yards. Here is how to bridge the gap.

The formula

cubic yards = length (ft) × width (ft) × depth (ft) ÷ 27

There are 27 cubic feet in a cubic yard because a yard is 3 ft on every side (3 × 3 × 3 = 27). That single number is the whole trick.

Worked example

A garden bed 10 ft × 12 ft, filled 4 inches deep:

1. Depth to feet: 4 ÷ 12 = 0.333 ft
2. Cubic feet: 10 × 12 × 0.333 = 40 ft³
3. Cubic yards: 40 ÷ 27 = 1.48 yd³

Inches-to-feet cheat sheet

Depth conversions you will reach for constantly:

Common mistakes

• Leaving depth in inches. Multiplying feet × feet × inches gives a number 12× too big. Convert depth to feet first.
• Rounding down your order. Suppliers deliver in half- or full-yard increments, and you lose a little to compaction and spillage. Round up.
• Measuring irregular shapes as one rectangle. Break an L-shaped area into two rectangles, calculate each, and add them.

Where you’ll use this

Cubic yards drive most landscaping orders. Once you have the volume, convert to a material weight with the gravel calculator or count bags with the mulch calculator. For bagged products measured in cubic feet, skip the ÷27 step and use the cubic feet calculator.

The University Extension services publish the same 27 ft³/yd³ conversion in their soil-volume guides — it is the standard for ordering bulk garden material.