Crushed Stone Calculator — #57, #8, #4, 3/4"
"Crushed stone" covers a family of products graded by size, all angular and roughly the same weight per cubic yard. The two numbers you'll trip on:
- Stone number = stone size. #57 = ~3/4 inch. #8 = ~3/8 inch. #4 = ~1.5 to 2.5 inch. Higher number, smaller stone (mostly).
- Density variations are small. All crushed stone in this family weighs 2,650–2,750 lb per cubic yard. The calculator picks the right average for the grade you select.
- #57: driveways, drainage, French drains — the all-purpose default.
- #8: paver bedding, fine surfaces, finishing layer.
- #4: deep base layers under driveways, erosion control, very heavy traffic.
- Crushed limestone: driveways and sub-bases in regions where it's the local stone.
"Washed" vs "unwashed" matters for drainage projects — washed stone has the dust rinsed off and is what you want for French drains and around perforated pipe. For driveway top course, unwashed (cheaper) is fine.
Crushed rock sizes at a glance
A quick size chart of the common grades, largest to smallest, with the weight per cubic yard and where each one fits:
| Grade | Size | Weight/yd³ | Common use |
|---|---|---|---|
| #4 | 1.5" – 2.5" | 2,650 lb | Deep base, erosion control |
| #57 | ¾" (¼" – 1½") | 2,750 lb | Driveways, drainage |
| #67 | ¼" – ¾" | 2,750 lb | Paver base top layer |
| #8 | ⅜" – ½" | 2,700 lb | Paver bedding |
| #10 (screenings) | dust – ⅛" | 2,700 lb | Joint filler, flagstone setting |
These size grades are defined by sieve analysis under ASTM C136/C136M, so a given grade means the same size envelope from quarry to quarry.
Recommended depth & material
| Use | Depth | Material | Notes |
|---|---|---|---|
| Driveway top course | 2" | #57 unwashed | Over a compacted base. |
| Driveway combined depth (refresh) | 4" | #57 | If skipping a separate base layer. |
| Driveway base (under top course) | 4" | #4 (deep) or ABC base | Then #57 on top. |
| French drain / drainage | 12" | #57 washed | Washed only — dust clogs the pipe. |
| Paver bedding | 1" – 2" | #8 stone | Or coarse concrete sand for finer setting bed. |
| Patio base | 4" | #57 | Or CA6 if pavers go on top. |
Crushed Stone Calculator — #57, #8, 3/4"
Crushed stone is sold by the ton — your measurement should land you within a half-ton of the right order. The calculator handles the rest.
- Pick your grade. Filter the material picker to the right stone number — #57 for general use, #8 for fine work, #4 for deep base layers. Crushed limestone is its own product (similar density to #57).
- Measure length × width. In feet, for the area you're filling. Use multi-area mode for irregular shapes.
- Set depth in inches. Use the depth presets if you're unsure. 4" is the all-purpose default for driveway/patio work.
- Specify washed if needed. Washed stone costs ~10% more but is mandatory for French drains, drainage projects, and any application where stone dust would clog something downstream.
- Add 10–15% buffer. 10% for clean rectangular jobs. 15% for trenches, slopes, or irregular shapes where the perimeter takes more material than the math says.
- Order in tons (US). Crushed stone is sold per ton at almost every quarry in North America. Confirm whether the price is delivered or picked-up before ordering.
Worked example: 200 sq ft of #57 stone, 4" deep
A 200 sq ft area — say a 10' × 20' parking pad or a 200 sq ft path:
- Volume: 200 × 4 ÷ 324 = 2.47 yd³
- Weight: 2.47 × 2,750 ÷ 2,000 = 3.4 tons
- With 10% buffer: ~3.7 tons of #57.
- Cost: at $40/ton (typical for #57 in many US markets), ~$148 in stone, plus an $80–$150 delivery fee.
Same area in #8 (smaller stone, slightly lower density) would come to about 3.3 tons. Same area in #4 (larger, denser): about 3.3 tons. The differences between grades are small at typical depths — the depth and area are the variables that move the order.