Crushed Stone Calculator

How to calculate how much crushed stone you need

Crushed stone is ordered by the ton or the cubic yard, and both come from three measurements. Measure length and width in feet and depth in inches, then:

Cubic yards = length (ft) × width (ft) × depth (in) ÷ 324
Tons = cubic yards × 1.35 (for #57 crushed stone)

The 324 is 12 inches per foot × 27 cubic feet per cubic yard, so you never convert the depth by hand. The calculator above defaults to #57 crushed stone and also has presets for crusher run (about 1.6 tons per yd³) and mixed gravel (about 1.4). These are typical planning values, not tested figures, so enter your supplier’s weight per yard when it gives one.

1. Measure the area. Split odd shapes into rectangles and add them.
2. Set the finished depth. Decide it before calling for quotes; depth drives the order more than anything else.
3. Pick the stone. Washed, single-size #57 is the default. Choose crusher run if the stone contains dust and fines.
4. Add 10% for settling, spillage and an uneven subgrade.

How much crushed stone for common sizes?

Most searches name a size: “crushed stone for a 10×10”, “20×20”, “1,000 sq ft”. This table answers them for #57 stone at 1.35 tons per yd³. Every figure comes from the same calculation the tool runs.

A handy check: at the 1.35 tons per yard this calculator assumes, #57 works out to 100 lb per cubic foot, so 1 ton is 20 ft³. A 20 ft² strip at 12 in deep, or 60 ft² at 4 in, is one ton.

How much does a ton of crushed stone cover?

One ton of #57 crushed stone covers about 120 ft² at 2 in deep, 80 ft² at 3 in and 60 ft² at 4 in. Heavier stone covers less: a ton of crusher run, at a typical 1.6 tons per yard, covers about 101 ft² at 2 in. The tons-per-yard figures in this table are typical planning values; check your supplier’s figure.

To turn coverage into an order, divide your area by the figure for your depth. A 450 ft² patio base at 4 in of #57 needs 450 ÷ 60 = 7.5 tons, or 8.25 tons with 10%. The per-yard column is the same for any stone because it is pure volume; only the per-ton columns depend on weight.

#57 stone calculator: tons per yard and coverage

To use this as a #57 stone calculator, keep the material on crushed stone (#57) and enter the area and depth. At the 1.35 tons per yard planning value, one ton of #57 covers about 60 ft² at 4 in deep, and one cubic yard covers 81 ft².

• 10 × 12 ft shed base, 4 in: 1.48 yd³ = 2 tons, or 2.2 tons with 10% extra.
• 12 × 20 ft pad, 4 in: 2.96 yd³ = 4 tons, or 4.4 tons with extra.
• French drain 12 in wide, 18 in deep, 50 ft long: 2.78 yd³ = 3.75 tons, or 4.13 tons with extra (less the volume of the pipe and fabric wrap, which is small).

If your quarry sells #57 at a different weight per yard, multiply the yards by its figure instead.

What size is #57 stone, and what are the other sizes?

#57 is a size number, not a rock type. The number comes from the AASHTO coarse-aggregate size system that state DOTs use, and it describes how much of the stone passes each sieve. An FHWA study of open-graded backfill lists the #57 band as:

In plain terms, almost everything is smaller than 1 inch, roughly 40–75% by weight is bigger than 1/2 inch, and there is next to no dust. That is what makes #57 “open-graded”: the angular pieces touch each other and leave voids that water can move through. It is the reason #57 is chosen for French drains, behind retaining walls, under pavers and as the middle layer of many driveways.

Other size numbers follow the same system. In the same FHWA table, 90–100% of #67 passes a 3/4 in sieve and all of #8 passes a 1/2 in sieve (85–100% passes 3/8 in), so both are finer than #57. Product names differ by region; some yards sell #57 as “3/4 in clean” or “1 in clean”. When the name is unclear, ask for the size number and whether the stone is washed. The weight per yard changes a little between sizes, so use the supplier’s figure when you have it.

Crusher run is different again. It is a dense-graded blend of crushed stone and stone dust that compacts hard. It has its own page: the crusher run calculator explains why its compacted weight per yard is higher than the loose figure.

How many tons of crushed stone in a yard?

This calculator uses 1.35 tons per cubic yard for #57 crushed stone, which is 2,700 lb, or 100 lb per cubic foot. It is a typical planning value, not a published standard. Rock type (limestone, granite, trap rock), moisture and how the stone is loaded all change it, so use your supplier’s figure when it gives one.

Converting quotes is the common need:

The reverse is just as simple: 10 yd³ of #57 at 1.35 tons per yard is 13.5 tons. If the quarry quotes a different weight per yard, multiply by that figure instead; the tons to cubic yards converter does the same with any weight.

Compacted, dense-graded aggregate is heavier than this. A Wisconsin DOT study measured compacted dense graded base at 1.78 to 1.98 tons per cubic yard. That figure applies to stone with fines, not to clean #57, but it explains why crusher run tonnage needs more allowance than #57.

Crushed stone for drains, sheds, pavers and driveways

The calculator handles all of these; what changes is the shape and depth.

French drains and trenches. Treat the trench as a long box. Each 10 ft of a 12 in wide trench takes 0.37 yd³ (0.5 tons) of #57 per foot of stone depth. A 4 in perforated pipe takes up about 0.087 ft² of the cross-section, so subtract 0.87 ft³ per 10 ft on long runs.

Shed and paver bases. A 4–6 in compacted stone base is common under sheds and pavers; follow the product’s or your designer’s instructions for paver bedding. A 12 × 12 ft base at 4 in is 2.4 tons of #57, and a 24 × 24 ft garage-sized pad at 4 in is 9.6 tons.

Driveways. Gravel driveways are built in layers: a coarse base, a middle layer such as #57 and often a crusher run top that packs down. On a 12 × 60 ft drive, a 4 in #57 layer is 8.89 yd³ (12 tons) and a 2 in crusher run top is 4.44 yd³ (7.11 tons). The driveway gravel calculator walks through every layer; this page sizes the #57 layer.

Crushed stone per square metre

Outside the US crushed stone is sold by the tonne, often as 20 mm or 40 mm stone. At the 1.35 US tons per yd³ this calculator assumes, it is about 1.6 tonnes per m³. That gives about 80 kg per m² at 50 mm and 160 kg per m² at 100 mm. A 5 × 4 m area at 50 mm is 1 m³, about 1.6 tonnes, or 1.76 tonnes with 10%.

How deep should crushed stone be?

Depth depends on what the stone has to do, and it is the single biggest driver of the order: 4 in uses twice as much stone as 2 in. Each extra inch of #57 adds 4.17 tons per 1,000 ft².

• Walkways and drainage beds: often 2–4 in of clean stone over landscape fabric. At 3 in, 1,000 ft² takes 12.5 tons.
• Shed and paver bases: usually 4–6 in, compacted in layers. A 12 × 16 ft base is 3.2 tons at 4 in and 4.8 tons at 6 in.
• Driveways: several layers adding up to more than any single-layer job, sized on the driveway gravel calculator.
• French drains and wall backfill: the depth is the trench or the wall height, often 12 in or more.

When a plan gives a finished depth, measure it after the stone is placed and settled. Clean #57 does not compact like crusher run, but it does settle into soft ground, which is part of what the 10% allowance covers.

Crushed stone behind a retaining wall

Many wall systems call for a zone of clean crushed stone directly behind the blocks so water can reach the drain instead of pushing on the wall. Follow the wall manufacturer’s drawing for the width and height of that zone; the volume is then a long box like a trench.

For a wall 30 ft long with a drainage zone 12 in wide and 3 ft high, the stone is 30 × 1 × 3 = 90 ft³, or 3.33 yd³. At 1.35 tons per yard that is 4.5 tons of #57, or 4.95 tons with 10%. A 4 in drain pipe at the base takes about 2.6 ft³ out of that, which is small enough to ignore at ordering time.

Enter the wall length as the length, the zone width as the width and the height in inches as the depth (36 in for 3 ft). The calculator then returns the same 3.33 yd³ and 4.5 tons.

Common mistakes when ordering crushed stone

Most orders go wrong on names and units rather than arithmetic. These are the costly ones, with their size.

• Ordering by name instead of size. “Gravel”, “clean stone” and “crushed rock” mean different things at different yards. Ask for the size number (such as #57) and whether it is washed.
• Using #57 where you need a packed surface. Clean #57 stays loose underfoot. For a firm top layer use crusher run, which on a 20 × 20 ft area at 4 in is about 7.9 tons at a typical 1.6 tons per yd³, versus 6.67 tons of #57.
• Confusing tons and yards. Ordering 4.94 tons for a 4.94 yd³ job (20 × 20 ft at 4 in) brings only 3.66 yd³, about 26% short.
• Entering depth in feet. A 10 × 10 ft area at 4 in is 1.23 yd³; typed as 4 ft it becomes 14.81 yd³.
• Forgetting the border. A 12 × 16 ft shed on a pad with a 1 ft border needs 4.2 tons, not 3.2.
• Skipping the extra. Stone settles into soft subgrade and spills at edges. On a 1,000 ft² base at 4 in, the 10% allowance is 1.67 tons.

Crushed stone calculator vs gravel, crusher run and driveway calculators: which one to use

This calculator is for angular crushed stone sized by number, with #57 as the default. Use a related tool when the job or the material is different:

• Gravel calculator: general gravel, pea gravel and landscape rock, with bag counts and circle and trench tables.
• Crusher run calculator: dense-graded base with fines, including the compacted-weight allowance it needs.
• Driveway gravel calculator: every layer of a new or refreshed gravel driveway.
• Pea gravel calculator and river rock calculator: rounded decorative stone for paths and beds.
• Tons to cubic yards: converting a quote between tons and yards for any stone.