You can estimate how much crushed stone you need with a simple formula using your project’s length, width, and depth.

Basic formula (rectangular areas)

  1. Measure:
    • Length LLL in feet
    • Width WWW in feet
    • Depth DDD in feet (remember: inches ÷ 12)
  2. Compute volume in cubic yards:

Cubic yards=L×W×D27\text{Cubic yards}=\frac{L\times W\times D}{27}Cubic yards=27L×W×D​

  1. To estimate tons (for typical crushed stone):

Tons≈cubic yards×1.4 to 1.7\text{Tons}\approx \text{cubic yards}\times 1.4\text{ to }1.7Tons≈cubic yards×1.4 to 1.7

Many guides use 1.4 as a common approximate factor.

Quick depth conversions

  • 2 inches = 0.17 feet
  • 3 inches = 0.25 feet
  • 4 inches = 0.33 feet
  • 6 inches = 0.5 feet

Rule of thumb:

  • 2 inch layer covers about 100 sq ft per 0.6–0.7 cubic yards.

Example: small patio

Say your patio area is:

  • Length: 16 ft
  • Width: 18 ft
  • Depth: 4 in (0.33 ft)
  1. Cubic yards:

(16×18×0.33)÷27≈3.5 cubic yards(16\times 18\times 0.33)\div 27\approx 3.5\text{ cubic yards}(16×18×0.33)÷27≈3.5 cubic yards

  1. Tons (using 1.4):

3.5×1.4≈4.9 tons3.5\times 1.4\approx 4.9\text{ tons}3.5×1.4≈4.9 tons

So you’d order about 3.5 cubic yards (≈5 tons) of crushed stone for that patio.

Add waste (so you don’t run short)

Most calculators suggest adding about 10% extra for waste, compaction, and low spots.

  • Adjusted cubic yards:

Needed×1.10\text{Needed}\times 1.10Needed×1.10

  • Example: 3.5 cubic yards →
    3.5×1.10≈3.853.5\times 1.10\approx 3.853.5×1.10≈3.85 cubic yards, so round to 4 cubic yards.

HTML-ready cheat sheet (rectangular areas)

html

<table>
  <thead>
    <tr>
      <th>Step</th>
      <th>What to do</th>
      <th>Formula / Note</th>
    </tr>
  </thead>
  <tbody>
    <tr>
      <td>1</td>
      <td>Measure length (L) and width (W) in feet</td>
      <td>Use a tape measure</td>
    </tr>
    <tr>
      <td>2</td>
      <td>Choose depth (D) and convert inches to feet</td>
      <td>D (ft) = depth in inches ÷ 12</td>
    </tr>
    <tr>
      <td>3</td>
      <td>Find volume in cubic yards</td>
      <td>Cubic yards = (L × W × D) ÷ 27</td>
    </tr>
    <tr>
      <td>4</td>
      <td>Convert to tons (typical crushed stone)</td>
      <td>Tons ≈ cubic yards × 1.4 to 1.7</td>
    </tr>
    <tr>
      <td>5</td>
      <td>Add 10% extra for waste</td>
      <td>Final amount = result × 1.10</td>
    </tr>
  </tbody>
</table>

If your area isn’t a simple rectangle

  • Multiple rectangles : Break the space into smaller rectangles, calculate each, then add the cubic yards together.
  • Odd shapes (curved, circular) :
    • Approximate with rectangles, or
    • Use an online stone or gravel calculator that supports different shapes and waste factors.

TL;DR

  • Use: cubic yards=(L×W×D)/27\text{cubic yards}=(L\times W\times D)/27cubic yards=(L×W×D)/27 with depth in feet.
  • Multiply cubic yards by about 1.4–1.7 for tons.
  • Add about 10% extra so you don’t run short.

If you tell me your length, width, and depth, I can walk you through the exact number for your project.

Information gathered from public forums or data available on the internet and portrayed here.