Crusher run, in plain English
Crusher run is whatever falls out of the rock crusher — the full size range from large pieces down to fine dust. The fines (the dust) are the magic ingredient: they fill the voids between bigger pieces and bind the whole mass together when wetted and compacted.
Same material, different regional names:
- Crusher Run / Crush and Run — most of the U.S.
- ABC (Aggregate Base Course) — Carolinas, Georgia
- GAB (Graded Aggregate Base) — Georgia DOT
- 21AA — Michigan
- CA6 — Illinois
- Class 5 — Minnesota
- MOT Type 1 — UK
Crusher run weight and coverage
Crusher run runs about 2,700 lb per cubic yard loose (what you order and pay for) and packs to roughly 3,200 lb per yard after compaction — it loses about 20% of its loose volume when you run a plate compactor over it. Here's how much loose material covers 100 square feet at common base depths:
| Depth | yd³ per 100 sq ft | Tons per 100 sq ft |
|---|---|---|
| 2" | 0.62 | 0.83 |
| 4" | 1.23 | 1.67 |
| 6" | 1.85 | 2.50 |
Multiply these by your area in hundreds of square feet, then add ~15% for compaction and spillage. The calculator above does the same math for any dimensions.
Recommended depth & material
| Use | Depth | Material | Notes |
|---|---|---|---|
| Light driveway base | 4" | Crusher Run / ABC | Topped with 2" of #57. |
| Heavy / RV driveway base | 6" | Crusher Run | Compact in 2-inch lifts. |
| Paver patio base | 4" | ABC / 21AA / CA6 | Same product, regional name. |
| Path / walkway base | 3" | Crusher Run | Compacted firm under pavers or pea gravel. |
| Shed pad | 4" | Crusher Run | Hard, weed-free surface. |
Measuring for a crusher run order
Crusher run is sold by the ton at virtually every U.S. quarry. Standard rectangular math: length × width × depth. Use a 15% buffer because crusher run loses ~20% of its loose volume during compaction.
- Length × width × depth. Measure in feet, depth in inches. Calculator does the conversion.
- Pick the depth. 4" for a passenger driveway base; 6" for trucks or soft soil.
- Apply 15% buffer. Covers compaction + spillage. Don't skip this — crusher run shrinks more than #57.
- Order in tons. Quarries quote crusher run by the ton. The calculator's tons output is what you order.
Worked example — 800 sq ft driveway base
An 80 × 10 ft driveway needing 4 inches of crusher run base: volume = 800 × (4/12) ÷ 27 = 9.9 yd³. At 2,700 lb/yd³, that's 13.4 tons. With a 15% compaction buffer: 11.4 yd³ / 15.4 tons. At $38/ton delivered: $585.