JLJosh Liljenquist

Construction & material calculator

Cubic yard calculator

Convert three project dimensions into cubic yards without first converting every measurement by hand. Each dimension can use a different unit, which is useful when a project is measured in feet but its depth is specified in inches.

By

Mixed unitsFormula shownNo account required

Enter project measurements

Enter measurements and select Calculate.

How to use this calculator

  1. Measure length and width at the project edges.
  2. Use the actual average depth if the surface is uneven.
  3. Choose the unit beside each measurement.
  4. Add waste only when the project or supplier calls for it.

Formula and method

Convert each dimension to one common unit, multiply length × width × depth, then convert volume. One cubic yard equals 27 cubic feet.

Worked example

A bed measuring 18 ft by 6 ft with a 4 in depth contains 36 ft³. Dividing by 27 gives about 1.33 yd³ before any allowance.

Assumptions and result interpretation

  • The calculation models a rectangular prism.
  • Irregular areas should be divided into simpler sections and totaled.
  • The result is volume; it does not estimate weight unless a material density is known.

Common mistakes

  • Dividing by 9 instead of 27
  • Leaving depth in inches while treating it as feet
  • Using outside dimensions when only an interior volume matters
  • Rounding each dimension before multiplying

Methodology sources

Conversions use deterministic factors. Variable material properties are either visibly sourced and editable or left for the user to enter from the supplier.

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Results are planning estimates. Confirm actual requirements with the appropriate supplier, contractor, engineer, building official, or other qualified professional.