Crushed Stone Calculator
Calculate how much crushed stone you need for driveway bases, foundation drainage, subbase layers, or backfill. Pick your application to set a recommended depth, choose your size grade (#57, #8, #4, #2, or custom), enter your project shape and dimensions, and see total tons, cubic yards, bag count, and coverage area. Crushed stone weighs about 100 lb per cubic foot (1,602 kg/m³).
Results
Estimates only. Coverage assumes loose-delivery density (100 lb/ft³). Actual in-place compacted volume runs 15 to 20 percent denser depending on application and equipment. Confirm minimum delivery quantities and bulk pricing with your supplier before ordering. TakeoffCalc isn't responsible for material over- or under-orders.
How to use this calculator
- 01Pick an application: driveway base, foundation drainage, subbase, backfill, or custom. The depth field auto-fills with a recommended value.
- 02Pick a size grade: #57 for driveway base, #8 for walkway dressing, #4 for heavy drainage, #2 for French drains, or custom for non-standard sizes.
- 03Pick a shape: rectangle, circle, or custom area for irregular shapes.
- 04Enter your dimensions and adjust depth if needed. Add a waste percentage for spillage and compaction.
- 05Read total tons, cubic yards, bag count, and coverage area at the top of the results panel. Add a price per ton for cost estimation.
Understanding the math
Crushed stone volume math is straightforward. Multiply the surface area by the depth to get cubic feet of material. Then multiply cubic feet by crushed stone’s bulk density (100 lb per cubic foot, or 1,602 kg/m³) to get pounds. Divide by 2,000 to convert pounds to tons. The waste and compaction percentage adds extra material to cover spillage, settling, and supplier minimums. Note that this uses loose-delivery density; actual in-place compacted volume runs roughly 15 to 20 percent denser.
volume_ft3 = area_ft2 × depth_ft weight_lbs = volume_ft3 × 100 weight_tons = weight_lbs / 2000 volume_yd3 = volume_ft3 / 27
Worked example. A driveway base 20 ft by 12 ft at 4 inches deep with 10% waste. Surface area is 20 × 12 = 240 sq ft. Depth in feet is 4 / 12 = 0.333 ft. Volume is 240 × 0.333 = 80 cubic feet. Weight is 80 × 100 = 8,000 lbs, which is 4 tons. With 10% waste added, you need about 4.4 tons (3.99 tonnes in metric).
Crushed stone size grades and coverage
Common ASTM D448 size grades for crushed stone with typical applications and coverage at recommended depths. Coverage values are based on loose-delivery density (100 lb/ft³ or 1,602 kg/m³) and assume rock spread evenly over a level surface. Compacted in place, expect roughly 15 to 20 percent more weight per area. Sources: ASTM D448 size-grade specification, USDA NRCS Practice Standard 378 for foundation drainage, AASHTO M 43 for road base classifications.
| Size Grade | Use Case | Recommended Depth | Coverage per Ton |
|---|---|---|---|
| #8 (3/8") | Walkway top dressing, fines | 2 in | 120 sq ft |
| #57 (3/4") | Driveway base, drainage | 4 in | 60 sq ft |
| #67 (3/4" with fines) | Drainage layer, subbase | 4 in | 60 sq ft |
| #4 (1.5") | Heavy drainage, subbase | 6 in | 40 sq ft |
| #411 (4-fines blend) | Compacted road base | 4 in | 60 sq ft |
| #2 (2") | French drains, foundation drainage | 12 in | 20 sq ft |
Frequently asked questions
How do I calculate how much crushed stone I need?
Multiply the surface area by the depth to get the volume of crushed stone you need. For a driveway base 20 ft by 12 ft at 4 inches deep, surface area is 20 × 12 = 240 sq ft, and depth in feet is 4 / 12 = 0.333 ft. Volume is 240 × 0.333 = 80 cubic feet.
To convert cubic feet to tons, multiply by crushed stone's density (about 100 lb per cubic foot) and divide by 2,000. So 80 × 100 / 2000 = 4 tons. Add a waste percentage of 10 to 15 percent for compacted applications like driveway bases, since loose-delivery density runs lighter than the in-place compacted material.
How much crushed stone do I need for a driveway?
A typical residential driveway base uses #57 stone (3/4") at a 4-inch installed depth. At that depth, 1 ton of crushed stone covers about 60 sq ft (6 m²). For a 600-square-foot driveway (20 ft by 30 ft), you'd need about 10 tons of #57 stone before waste.
Add 10 to 15 percent for compaction loss since driveway gravel gets compacted heavily by traffic. So a 600 sq ft driveway typically takes 11 to 12 tons total. For longer driveways or use under heavy vehicles, contractors often spec a deeper base (6 inches) or a layered approach (#4 underneath, #57 on top).
What is the difference between #57 and #8 crushed stone?
#57 stone is approximately 3/4-inch washed crushed stone with no fines (small particles). It drains well and is the most common size for driveway bases, French drains, and concrete aggregate. The angular shape locks together but doesn't compact tightly, which is why it works well for drainage applications.
#8 stone is approximately 3/8-inch washed crushed stone, much smaller. It's used for walkway top dressing, paver setting beds, and as fines material to fill voids in larger stone bases. #8 is too small for primary driveway base use because it migrates and doesn't lock well under vehicle loads. Both share the same loose-delivery density (about 100 lb per cubic foot), so the math for tonnage is identical at the same depth.
How much does a ton of crushed stone cover?
Coverage depends on depth. At 2 inches deep, 1 ton of crushed stone covers about 120 sq ft (12 m²). At 4 inches deep, coverage drops to about 60 sq ft (6 m²). At 6 inches deep, coverage is about 40 sq ft (4 m²). At 12 inches deep (typical for French drain backfill), coverage is about 20 sq ft (2 m²). The reference table above shows coverage at common depths for typical ASTM size grades.
The math works backward from density. 1 ton equals about 20 cubic feet of crushed stone at 100 lb per cubic foot loose-delivery density. Divide that by your depth in feet to get the area covered.
What size crushed stone should I use?
Match size to application. #57 (3/4") is the workhorse for driveway bases, French drains, and most general drainage. #8 (3/8") works for walkway top dressing, paver setting beds, and filling voids in larger stone. #4 (1.5") provides heavy drainage and structural subbase for road and parking lot construction. #2 (2") is reserved for foundation drainage, large French drains, and erosion control where high flow capacity matters.
Subbase layering is common for high-load applications. Contractors often spec #4 stone underneath #57 stone for driveways carrying heavy vehicles, or #2 stone at the bottom of foundation drainage with #57 above. The reference table above pairs typical size grades with recommended applications and depths.
Can I use this calculator with metric measurements?
Yes. The unit toggle at the top of the form switches every input between imperial and metric. Length and width fields accept feet or meters. Depth accepts inches or centimeters. Custom area accepts square feet or square meters.
The output panel shows tons in imperial mode and tonnes in metric mode. Volume rows flip between cubic yards / cubic feet and cubic meters. Bag count uses 0.5 cubic foot bags in imperial and 14 liter bags in metric, matching common retail bag sizes.
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