Stone calculator for Montana

Use this page to estimate tonnage for graded stone, including 3/8 inch chips and railroad ballast.

Enter your project dimensions

Length (feet)

Enter a length greater than 0

Width (feet)

Enter a width greater than 0

Diameter (feet)

Enter a diameter greater than 0

Depth (inches)

Enter a depth between 0.25 and 24 inches

Material

Add 5% extra for compaction & spillage

Stone is sold by the ton. For most grades, use about 2,800 lb per cubic yard, which equals 1.4 tons per yard. This crushed-stone calculator accounts for all twelve graded product choices, ranging from 3/8 inch chips through 2.5 inch railroad ballast, using the selected material's weight. A contractor may begin with a specification, while a homeowner may start with the project itself. The result is the same material, with the notes below connecting those two approaches.

Calculation steps

For a pad or drive, multiply length by width in feet. For a drain, use trench length multiplied by trench width.
Choose depth based on the layer's role: 2 to 3 inches for a top course, 4 inches for base, and 12 inches or more for a French drain.
To get cubic yards, divide cubic feet by 27. For typical crushed stone tons, multiply yards by 1.4.

Tons = (Area sq ft × Depth in ÷ 12) ÷ 27 × 1.4

Product stone weights

Product	Weight per cubic yard	Tons per yard
#57 / #67 / 3/4" crushed stone	≈ 2,800 lb	1.40
#89 / #8 / 3/8" chips	≈ 2,800 lb	1.40
Stone screenings / dust	≈ 2,900 lb	1.45
Crusher run / road base	≈ 3,000 lb	1.50
#4 stone / railroad ballast	≈ 2,900 lb	1.45
Rip rap	≈ 3,100 lb	1.55

Depth	1 cubic yard covers	1 ton covers
2 inches	162 sq ft	≈ 116 sq ft
3 inches	108 sq ft	≈ 77 sq ft
4 inches	81 sq ft	≈ 58 sq ft
6 inches	54 sq ft	≈ 39 sq ft

Reading stone size labels

Grade names describe particle-size ranges, with a lower number indicating larger stone. #4 measures 1 to 2 inches. For general drainage, driveways, and concrete work, #57 ranges from 3/4 to 1 inch. #67, often placed as pipe bedding, is finer at 1/4 to 3/4 inch. #8 is about 3/8 to 1/2 inch, and #89 extends from 3/8 inch down to fines; these finer materials are used for paver joints and finish layers. Compacted screenings, made of dust and chips, create a firm bed that can be screeded. Railroad ballast consists of angular rock measuring 1 to 2.5 inches, providing load support and rapid drainage beneath tracks and equipment pads.

Clean stone or fines: select by purpose

Stone here falls into two material types. Washed stone, including #57, has open voids that let water through, making it suited to drainage. Crusher run and road base contain fines that compact into a firm layer, making them suited to bases. Using each in the wrong place causes problems: crusher run in a French drain can retain water, while a #57 driveway base can keep moving. When a plan or permit specifies a gradation, use that stated material. If the name is unclear, send the line item through our contact form. "3/4 clean" and "#57" can refer to the same rock under different names.

Common stone quantities

Project	Typical size	Depth	Volume	Weight
French drain	30 ft x 12" x 12"	12"	1.1 yd³	1.6 tons
Pipe bedding (#67)	40 ft x 18" wide	6"	1.1 yd³	1.6 tons
Retaining-wall backfill	30 ft x 18" wide	24"	3.3 yd³	4.7 tons
Construction entrance (#4)	40 x 12 ft	6"	8.9 yd³	12.9 tons
Dog run	15 x 8 ft	3"	1.1 yd³	1.6 tons
Shed pad top course	10 x 12 ft	2"	0.7 yd³	1 tons

Example calculation: 30-foot French drain

For a trench measuring 30 feet long by 12 inches wide by 12 inches deep, the volume is 30 cubic feet, equal to 1.1 cubic yards or 1.6 tons of #57. A 4-inch pipe centered in the trench takes up only about 0.1 yards, so order the full 1.6 tons and place the slight extra at the outfall. Before adding stone, line the trench with non-woven fabric to keep soil from filling the drainage voids.

Two ways to improve a stone order

Use the specification first and verify the local name afterward. Crusher run, crush and run, Pit Run, bank run and pit gravel are names for one product; #57 and "57s" also mean the same stone.
Plan on 5 to 10% compaction for angular stone that will be rolled. The calculator's extra-percent toggle accounts for ordinary settling. For engineered base, use the specified compacted depth.
A paver installation needs compacted base stone for support, with screenings or concrete sand as the thin leveling layer. Do not place pavers on dust alone where ground is soft.
Calculate the trench volume instead of deducting the pipe. A pipe below 6 inches seldom displaces more material than a wheelbarrow load.

Crushed stone reference figures

What does a cubic yard of crushed stone weigh?

Common sizes such as #57 and 3/4 inch weigh about 2,800 lb per yard, or 1.4 tons. Heavier materials include crusher run at 3,000 lb and riprap at 3,100 lb per yard.

What area will a ton of #57 cover?

At a depth of 2 inches, one ton covers roughly 116 square feet. At 3 inches, coverage is 77 square feet, and a 4-inch base depth covers 58 square feet.

How do #57, #67 and #89 differ?

The labels identify stone size. #57 measures 3/4 to 1 inch; #67 measures 1/4 to 3/4 inch; and #89 runs from 3/8 inch to fines. #57 and #67 are used for drainage and driveways, while finer grades suit paths, joints, and finish layers.

Recommended driveway stone depth

For a new drive, install 3 to 4 inches of compacted crusher run, then add 2 to 3 inches of #57 or driveway gravel. Deep frost makes proper base depth important. An existing drive needs 2 inches of surface stone for a top-up.

Stone dust or sand below pavers?

Beneath pavers, the materials serve separate layers. Compacted stone forms the base, with screenings or coarse concrete sand above it in a 1-inch leveling bed. Pure dust in a thick layer can retain water and pump when loaded.

Which stone size works for a French drain?

Use clean #57 or drain rock and wrap it in non-woven geotextile. Keep fines out, because they clog the drain.

Will crushed stone compact?

Traffic can compact angular clean stone by about 5 to 10%. Blended material with fines compacts more as intended. Include the small excess with the original order rather than arranging a half ton top-up delivery.

Uses for railroad ballast beyond rail lines

Use this rock where loads cross wet ground, including equipment pads, construction entrances, and farm tracks. Its angular 1 to 2.5 inch pieces interlock under load while allowing water to drain.

Gravel CalculatorCalculate →Crusher Run CalculatorCalculate →Rip Rap CalculatorCalculate →All calculatorsMulch, sand, topsoil, dirt & more.Open the hub →

Stone grades by specification

Twelve graded stone products are priced per ton, with free delivery across Montana.

Shop #57 Stone