Gravel Calculator

Area to cubic yards, tons and coverage

"Gravel Calculator" Calculator

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Gravel: the Formula, the Coverage and What a Yard Weighs

How much gravel an area needs

Gravel is bought by volume, so the question «how much» is a volume question. For a rectangular area it is one multiplication and one division:

cubic yards = square feet × depth in inches ÷ 324

The 324 is not a rule of thumb. A cubic yard is 3 × 3 × 3 feet = 27 cubic feet; spread one inch deep it becomes a sheet 27 × 12 = 324 square feet across. Divide 324 by the depth you want and you have the coverage of one yard; multiply the area by the depth and divide by 324 and you have the yards you need. Nothing in that chain depends on what the gravel is made of, which is why the volume is exact and the weight is not.

Step by step

  1. Measure the area in square feet. Width × length for a rectangle; split anything else into rectangles and add them up.
  2. Choose the depth in inches. 1–2 inches for decorative gravel around plants, 4–6 inches for a path or driveway over a compacted base.
  3. Multiply and divide by 324. That is the answer in cubic yards. Multiply by 27 instead of dividing by 324 if you want cubic feet.
  4. Add 10% if the load will be stockpiled. This is the allowance the WSDOT Design Manual gives for waste in handling.

How much one cubic yard covers

This is the second question the topic asks, and the answer only depends on depth — not on the material:

Depth One cubic yard covers Gravel for 100 square feet Typical use
1 inch324 square feet0.31 cubic yards light top-up over existing stone
2 inches162 square feet0.62 cubic yards decorative gravel around plants
3 inches108 square feet0.93 cubic yards deep decorative layer, weed suppression
4 inches81 square feet1.23 cubic yards path surface over a base
6 inches54 square feet1.85 cubic yards driveway, in two compacted layers

What a cubic yard of gravel weighs

This is the single most asked question about gravel, and most calculators answer it with one number and no indication of which number it is. There are two, and they differ by about 20%:

  • Truck measure — 2,850 to 3,100 lbs per cubic yard (1.43–1.55 tons). This is the state the material arrives in, loose in the bed, and the state you are billed for.
  • Compacted in place — 3,400 to 3,800 lbs per cubic yard (1.70–1.90 tons). This is what the same gravel weighs after it is spread and rolled, and it is the figure a specification uses.

Both come from the WSDOT Design Manual M 22-01.23 (September 2024), Exhibit 620-1, «Unit Dry Weight — Gravel Base and Surfacing».

Two honest limits on those numbers. First, the source is about road gravel — gravel base, crushed surfacing, ballast — not about the pea gravel sold for a garden path; the grading is different and so is the density. Second, «Weights shown are dry weights and corrections are required for water contents»: wet material is heavier, and after rain noticeably so.

What people are actually working out

  • Ordering by the yard: bulk suppliers quote per cubic yard, so the volume is the number to phone in — and the 10% stockpile allowance is worth adding before you do.
  • Ordering by the ton: some yards sell by weight instead. A yard is roughly one and a half tons at truck measure, so the two numbers are not interchangeable and neither is the price per unit.
  • Checking the load: a cubic yard weighs about a ton and a half, so a pickup rated for half a ton is full at roughly a third of a yard. The weight, not the volume, is what runs out first.
  • Landscape fabric and edging: both are bought by the area, which is the number you started with, not by the volume.
  • Driveways: planned as layers — a coarse base and a finer surface — so each layer is its own depth and its own calculation.

Where the formula stops working

  • The area must be flat and rectangular. Split an L-shape into rectangles; for a circle use π × radius².
  • Loose volume is not compacted volume. Gravel settles as it is rolled: order by loose volume and expect the finished layer to be thinner than the depth you bought.
  • Density is a property of the specific stone. Grading, mineral and moisture all move it, which is why the weight here is a range and not a figure.
  • A driveway is a structure, not a layer of stone. Depth, base preparation and drainage are decided by the traffic it carries, and no volume calculator answers that.

Doing it in your head

Remember one number: 324. One cubic yard, one inch deep, covers 324 square feet — so at 2 inches a yard does about 160 square feet, at 3 inches about 110, at 4 inches about 80. Divide your area by that and you have the yards, near enough to phone in an order.

Gravel for common areas

At the default depth of 2 inches, with the weight as delivered:

Area Gravel Cubic feet Weight
30 square feet0.19 cubic yards5 cubic feet542–589 lbs
50 square feet0.31 cubic yards8.33 cubic feet884–961 lbs
60 square feet0.37 cubic yards10 cubic feet1,055–1,147 lbs
80 square feet0.49 cubic yards13.33 cubic feet1,397–1,519 lbs
100 square feet0.62 cubic yards16.67 cubic feet1,767–1,922 lbs
120 square feet0.74 cubic yards20 cubic feet2,109–2,294 lbs
150 square feet0.93 cubic yards25 cubic feet2,651–2,883 lbs
160 square feet0.99 cubic yards26.67 cubic feet2,822–3,069 lbs
200 square feet1.23 cubic yards33.33 cubic feet3,506–3,813 lbs
250 square feet1.54 cubic yards41.67 cubic feet4,389–4,774 lbs
300 square feet1.85 cubic yards50 cubic feet5,273–5,735 lbs
400 square feet2.47 cubic yards66.67 cubic feet7,040–7,657 lbs
500 square feet3.09 cubic yards83.33 cubic feet8,807–9,579 lbs
600 square feet3.7 cubic yards100 cubic feet10,545–11,470 lbs
800 square feet4.94 cubic yards133.33 cubic feet14,079–15,314 lbs
900 square feet5.56 cubic yards150 cubic feet15,846–17,236 lbs
1,000 square feet6.17 cubic yards166.67 cubic feet17,585–19,127 lbs
1,200 square feet7.41 cubic yards200 cubic feet21,119–22,971 lbs
1,500 square feet9.26 cubic yards250 cubic feet26,391–28,706 lbs
2,000 square feet12.35 cubic yards333.33 cubic feet35,198–38,285 lbs
No prices here, on purpose. What a yard of gravel costs depends on the pit, the haul distance and the week; we have no data on any of the three, so this page answers volume, coverage and weight and leaves the price to your supplier.

See Also

About "Gravel Calculator" Calculator

This calculator works out how much gravel an area needs: enter the area and it returns the volume in cubic yards and cubic feet, the weight range in pounds and tons, and how much ground one cubic yard covers. For example, it can help you find out how much gravel do I need for 200 square feet? (The answer is: 1.23 cubic yards). Enter the area (e.g. 200 square feet), choose the unit and set the depth — 2 inches by default, anything from 1–24 inches is accepted and gets its own page.

FAQ

How much gravel do I need?

Multiply the area in square feet by the depth in inches and divide by 324 — that gives cubic yards. A 200 sq ft patch at 2 inches deep is 200 × 2 ÷ 324 = 1.23 cubic yards, or 33.33 cubic feet.

How much does a yard of gravel weigh?

As delivered — truck measure — a cubic yard of gravel base runs about 2,850 to 3,100 pounds, roughly 1.43 to 1.55 tons. Compacted in place the same material is 3,400 to 3,800 pounds per cubic yard. Figures are from the WSDOT Design Manual M 22-01.23, Exhibit 620-1, and they are dry weights: wet gravel is heavier.

How much area does a yard of gravel cover?

One cubic yard spread 1 inch deep covers 324 square feet. Divide that by your depth: 162 square feet at 2 inches, 108 at 3 inches, 81 at 4 inches, 54 at 6 inches.

How deep should gravel be?

For decorative gravel used as a mulch around plants, 1 to 2 inches is the range extension services give. A gravel driveway or path is a different job and wants 4 to 6 inches, usually in more than one layer over a compacted base — do not use the mulch depth for it.

How much extra gravel should I order?

The WSDOT Design Manual says to increase required quantities by 10 % when material is stockpiled, to allow for waste. The result page prints that figure next to the exact volume.

Is gravel sold by the yard or by the ton?

Both, and they are not interchangeable: a yard is a volume and a ton is a weight, and the number that connects them is the density. At truck measure one cubic yard is about 1.43 to 1.55 tons, so an order in tons is roughly one and a half times the number of yards.