Getting the quantity right before you order saves you from two equally frustrating outcomes: running short on the day of delivery when the supplier’s next available slot is a week away, or paying for a large surplus that sits unused on your property.
Crusher run quantity calculations are straightforward once you understand the relationship between area, depth, compaction, and tonnage. This guide walks through the formula step by step, provides a worked example, and includes a reference table for common project dimensions.
The Key Variable: Compacted vs Loose Depth
Before running any calculation, it is important to clarify which depth you are working with.
Crusher run compacts by approximately 20 percent under a plate compactor. This means that 5 inches of loose material compacts to approximately 4 inches, and 6 inches of loose material compacts to approximately 5 inches.
Quantities are almost always calculated using loose depth, because that is the volume you are ordering and receiving from the supplier. However, depth requirements such as those in the how deep should crusher run be guide are stated as compacted depths, because that is the finished dimension that matters for structural performance.
To convert a compacted depth requirement to the loose depth you need to order, multiply the compacted depth by 1.25.
- 4 inches compacted = 5 inches loose
- 6 inches compacted = 7.5 inches loose
All calculations in this guide use loose depth, since that is what you are ordering.
The Tonnage Formula
The standard formula for calculating crusher run in tons is:
(Length in feet x Width in feet x Depth in inches) / 12 / 27 x Bulk density in tons per cubic yard
Breaking that down:
- Dividing by 12 converts depth from inches to feet, giving you volume in cubic feet.
- Dividing by 27 converts cubic feet to cubic yards.
- Multiplying by bulk density converts cubic yards to tons.
The bulk density of crusher run is approximately 1.35 tons per cubic yard for standard 3/4 inch limestone crusher run at typical moisture content. Granite crusher run is slightly heavier at around 1.45 tons per cubic yard.
The simplified formula using the 1.35 figure is:
(Length x Width x Loose depth in inches) x 0.005
This gives you tons of material to order, before adding a waste factor.
Waste Factor
Always add a 10 percent waste factor to your calculated quantity to account for minor variations in depth across the project area, material lost during spreading and compaction at edges, and any soft spots that require extra material. Ordering slightly more than the minimum calculated quantity is much less disruptive than running short.
Final order quantity = calculated tons x 1.10
Worked Example: Standard Two-Car Driveway
Project: A two-car residential driveway, 20 feet wide by 50 feet long, with a 6-inch total compacted depth (4-inch base layer plus 2-inch surface layer).
Step 1: Convert compacted depth to loose depth
6 inches compacted x 1.25 = 7.5 inches loose depth
Step 2: Calculate base tonnage
20 x 50 x 7.5 x 0.005 = 37.5 tons
Step 3: Add 10 percent waste factor
37.5 x 1.10 = 41.25 tons
Order: 42 tons (rounding up to the nearest whole ton).
At a material price of $25 per ton, this project’s material cost would be approximately $1,050 before delivery. Use the crusher run cost guide for current regional pricing to build a full budget estimate.
Calculating for a Two-Layer Installation
If you are building a two-layer driveway, you may be using different gradations for the base and surface layers. In that case, calculate each layer separately using the same formula and add the results together.
Base layer: 20 x 50 x 6.25 (5 inches loose = 4 inches compacted) x 0.005 = 31.25 tons x 1.10 = 34.4 tons
Surface layer: 20 x 50 x 3.75 (3 inches loose = 2.4 inches compacted, close enough to 2 inches compacted for ordering purposes) x 0.005 = 18.75 tons x 1.10 = 20.6 tons
Combined: approximately 55 tons for the complete installation.
Note that in most residential projects, both layers use the same 3/4 inch crusher run product, and you can simply add the loose depths together and calculate as a single order. The two-layer calculation is most useful when the base and surface use different gradations from different suppliers.
Ready-Reference Table
The table below gives pre-calculated quantities for common project dimensions and compacted depths. All figures include the 10 percent waste factor and assume a bulk density of 1.35 tons per cubic yard.
Driveway Dimensions (tons of crusher run, including 10% waste)
| Area (sq ft) | 4 in compacted | 6 in compacted | 8 in compacted |
|---|---|---|---|
| 200 (10 x 20) | 7.5 | 11.0 | 14.9 |
| 400 (10 x 40 or 20 x 20) | 14.9 | 22.3 | 29.7 |
| 600 (12 x 50 or 20 x 30) | 22.3 | 33.4 | 44.6 |
| 800 (20 x 40) | 29.7 | 44.6 | 59.4 |
| 1,000 (20 x 50) | 37.1 | 55.7 | 74.3 |
| 1,500 (20 x 75 or 30 x 50) | 55.7 | 83.6 | 111.4 |
| 2,000 (20 x 100 or 40 x 50) | 74.3 | 111.4 | 148.5 |
Patio and Shed Base Dimensions (tons of crusher run, including 10% waste)
| Area (sq ft) | 4 in compacted | 6 in compacted |
|---|---|---|
| 100 (10 x 10) | 3.7 | 5.6 |
| 150 (10 x 15 or 12 x 12) | 5.6 | 8.4 |
| 200 (10 x 20 or 14 x 14) | 7.5 | 11.2 |
| 300 (12 x 25 or 15 x 20) | 11.1 | 16.7 |
| 400 (16 x 25 or 20 x 20) | 14.9 | 22.3 |
Converting Tons to Loads
Once you have a total tonnage, you can estimate how many truck loads you will need by dividing by the typical truck capacity in your area. A standard dump truck carries 10 to 14 tons. A tandem axle truck carries 14 to 18 tons. Ask your supplier what size vehicle they use for delivery so you know how many loads to expect.
For a project requiring 42 tons, you would expect three to four standard dump truck loads.
Calculating for Irregular Areas
If your driveway or project area is not a simple rectangle, break it into sections that can each be approximated as rectangles, calculate each section separately, and add the results together. Include the 10 percent waste factor on the total rather than on each section individually.
For a more complete grounding in crushed stone quantity calculation methods including worked examples for irregular shapes, the how to calculate crushed stone for a driveway guide covers the same principles applied to clean crushed stone, and the methodology transfers directly to crusher run calculations.
Frequently Asked Questions
How many tons of crusher run do I need per square foot?
At a compacted depth of 4 inches, you need approximately 0.025 tons of crusher run per square foot. At 6 inches compacted depth, approximately 0.037 tons per square foot. Multiply by your total square footage and add 10 percent for waste and compaction variance.
How many cubic yards of crusher run do I need?
Divide your area in square feet by 324 for a 1-inch depth, then multiply by your intended depth in inches. This gives you cubic yards of loose material. Crusher run compacts by around 20 percent, so the loose volume you order will be greater than the compacted volume you end up with.
How much does a ton of crusher run cover?
One ton of crusher run covers approximately 80 square feet at a compacted depth of 2 inches, 54 square feet at 3 inches compacted, and 40 square feet at 4 inches compacted. These figures account for the compaction factor.
How much crusher run do I need for a driveway?
A standard two-car driveway measuring 20 feet wide by 40 feet long (800 square feet) with a 6-inch total compacted depth requires approximately 30 tons of crusher run. A single-car driveway of 10 by 40 feet (400 square feet) at the same depth requires approximately 15 tons.