Gravel Calculator

What this gravel calculator does

Gravel is sold by the cubic yard, by the ton and by the bag, and suppliers rarely agree on which one to quote. That mismatch is a common source of ordering mistakes: you measure in feet, the quote arrives in tons, and nothing has been converted in between. This gravel calculator takes the size of your area and the depth you want, then gives you all three, plus the cost if you add a price.

Beyond the totals, it shows how your order changes if the depth is a little more or less, compares the weight of six common stones for your exact job, and works out how many pickup trips the load will take once you account for payload. You can switch to metric for tonnes and cubic metres, which is how many suppliers outside the United States sell chippings.

Everything runs in your browser. Nothing you type is stored or sent anywhere.

How to use the calculator

1. Pick a shape. Use Rectangle for a driveway, path or bed, Circle for round areas, or By area if you already know the total. For odd shapes, the square footage calculator will give you the area.
2. Enter the size and depth. The Project type menu fills in a typical depth, and you can overwrite it with any number.
3. Choose the stone. Weight per cubic yard differs between gravel, pea gravel and crusher run, so the choice changes your tons.
4. Open the optional extras. Set the extra allowance, add your supplier’s weight if you have one, and enter a price or your truck’s payload. Tap the small i beside any option for an explanation.
5. Read the results. You get cubic yards, tons, bags, cost, two charts and an order plan.

How much gravel do I need?

The short method: multiply the area in square feet by the depth in feet to get cubic feet, divide by 27 for cubic yards, and add about 10 percent. Most gravel weighs close to 1.4 tons per cubic yard, so multiply the yards by 1.4 for a rough tonnage. For a quick check, one cubic yard covers about 81 square feet at 4 inches deep and 162 square feet at 2 inches.

The table shows what that gives for common jobs. It uses general gravel at 2,800 pounds per cubic yard with 10 percent extra.

Treat these as starting points, because uneven ground and the stone you choose will move the numbers.

How to calculate yards of gravel, step by step

If you want to check the calculator by hand, or work out a quick figure on site, the method is the same cubic-yard math used in the concrete yard calculator.

1. Find the area. Multiply length by width. For a circle, multiply 0.7854 by the diameter squared.
2. Convert the depth to feet. Divide the inches by 12, so 4 inches is 0.333 feet.
3. Multiply for cubic feet. Area times depth in feet.
4. Divide by 27. That gives cubic yards, because a cubic yard holds 27 cubic feet.
5. Add extra. About 10 percent covers spillage, uneven ground and settling.
6. Convert to tons. Multiply the yards by the stone’s weight per cubic yard, then divide by 2,000.

When the depth is in inches, there is a shortcut for yards: area in square feet times depth in inches, divided by 324. The 300 square foot strip gives 300 × 4 ÷ 324 = 3.70, the same answer.

Which gravel for which job

Stone names vary by supplier, but these types cover most jobs.

• Crusher run or road base. Crushed stone mixed with fine dust. The fines let it pack tightly, which makes it a common choice for driveway bases and under pavers.
• Clean crushed stone, about 3/4 inch. Angular pieces with little dust. It drains well and suits drainage trenches and the top layer of a driveway.
• Pea gravel. Small and rounded. It is comfortable underfoot, so it is used for paths and garden beds.
• River rock. Larger smooth stones, mostly decorative, used in beds and around drainage channels.
• Decomposed granite. Fine granite particles that compact into a firm surface for paths and patios.

How much does gravel weigh? Tons, yards and bags

Weight causes much of the confusion. A cubic yard of stone does not weigh the same for every type, and a supplier who sells by the ton needs a different number from one who sells by the yard. These are the planning figures the calculator uses.

In practice, a ton of general gravel fills about 0.71 cubic yards. So how many cubic yards in a ton of rock? Between roughly 0.67 and 0.77, depending on the type. Moisture adds weight, and different quarries produce slightly different material. If your supplier quotes a weight, type it into the optional box and the calculator will use it. For river rock or other decorative rock, pick that material in the menu: the volume math is identical and only the weight changes.

For bags, general gravel works out to about 104 pounds per cubic foot, so a 0.5 cubic foot bag weighs around 52 pounds. Always check the weight and volume printed on the bag you buy.

How far does a ton of gravel go?

Coverage answers the opposite question: how much area does one ton cover? It depends only on the depth and the weight of the stone.

Use the table to sanity-check a quote. If someone tells you a 400 square foot area at 4 inches needs 3 tons, the table shows a ton covers about 58 square feet, so you would need closer to 7.

Gravel for a driveway

A good gravel driveway calculator has to handle layers, because a driveway is usually built in them. A common approach is a base of larger crushed stone for strength and drainage, topped with a smaller stone that locks together. Total depth is often somewhere between 4 and 6 inches, but soil, traffic and local rules all matter, so check what applies to you.

Run the calculator once for each layer and add the tons. A 12 by 40 foot driveway with a 4 inch base and a 2 inch top layer needs 5.93 and 2.96 cubic yards, which is the same 8.89 cubic yards as a single 6 inch layer before extra. The weights differ if the two layers use different stone, and that is the reason to calculate them separately.

Loose stone compacts, so a base that will be rolled or tamped needs a larger extra allowance than a top dressing that is only raked. A layer of landscape fabric under the stone is a common way to keep the soil and stone from mixing. If the gravel is the base for a concrete slab, size the slab with the concrete yard calculator and budget it with the concrete slab cost calculator.

Pea gravel: how much do you need?

Pea gravel is small, smooth, rounded stone, roughly pea-sized and up to about 3/8 inch. Because it is round, it shifts underfoot, so paths and slopes need edging to hold it in.

Calculating pea gravel uses the same method, but the weight is a little higher than general gravel. A 10 by 10 foot area at 2 inches needs 0.62 cubic yards, or 0.68 with 10 percent extra. At 2,900 pounds per cubic yard that is about 0.98 tons. The calculator runs this same calculation when you choose Pea gravel, so it answers how much pea gravel you need for any size.

Gravel in tonnes: chippings and metric orders

If you are in the UK, Ireland, Australia or much of Europe, you will often see gravel sold by the tonne, and decorative stone is often called chippings. Switch the Units menu to Metric and the calculator works in metres, centimetres, cubic metres and tonnes.

For example, how much chippings do you need for 20 square metres at 5 centimetres deep? The volume is 20 × 0.05 = 1.0 cubic metre. At about 1,660 kilograms per cubic metre that is 1.66 tonnes, or 1.83 tonnes with 10 percent extra. Ask your supplier whether the price is per tonne or per cubic metre before you compare quotes.

Bulk, bags or a pickup load

Weight, not volume, decides how you can move gravel. A cubic yard of general gravel weighs about 2,800 pounds, so a pickup rated to carry 1,500 pounds can only take around half a cubic yard in one trip, even though the bed looks big enough for more. The driveway strip above is 11,400 pounds with extra, which is about eight trips. The sticker in your driver’s door jamb lists the load limit, and you should never go past it.

Bags tell the same story. That same job is 220 bags of 0.5 cubic feet, which is a lot to lift and load. Bags suit small jobs such as a few planters. Once you need around a cubic yard or more, get a bulk delivery quote as well, since it is often the simpler option. The order plan in the results shows the trips and bags for your numbers.

How much does gravel cost?

People ask how much is a yard of gravel, or how much is a ton of gravel, and the answer depends on where you live. Stone type, haul distance, season and delivery fees all move the price, and many yards charge a minimum load or a flat delivery fee. Ask two or three suppliers for a delivered price.

The calculator multiplies your quantity by the price you enter and adds the delivery fee. To compare a price per ton with one per cubic yard, multiply the per-ton price by the tons in a yard. For general gravel at 1.4 tons per yard, a price of 40 per ton is about 56 per cubic yard. These are example numbers, not quotes.

Common gravel mistakes

• Mixing volume and weight. A quote in tons and a quote in yards are not comparable until you convert one of them.
• Measuring depth once. Check it at several points, because low spots swallow stone.
• Ignoring compaction. A base that gets compacted ends up thinner than the loose depth you spread.
• Skipping the edging. Loose stone migrates onto lawns and paths, and pea gravel migrates fastest.
• Digging without checking. Before you excavate for a base, find out where buried lines run.

Sources and further reading

The volume formulas are standard geometry, and a cubic yard is exactly 27 cubic feet. The stone weights are typical planning figures that vary by quarry and moisture, so confirm them with your supplier.

• NIST Special Publication 811, unit conversion factors.
• National Stone, Sand & Gravel Association, industry information on aggregates.
• Call 811, free service to mark buried utility lines before you dig in the United States.

Requirements for driveways and bases vary by location, so confirm the rules with your local building or highway department. For more tools like this one, browse the concrete calculators hub.

Gravel calculator FAQs

About the author. I’m Shivam, a software engineer and the founder of Calctoolz. I research each formula in its original source and then build the logic exactly as defined, so the numbers you see can be checked by hand. Read more about Calctoolz or find me on LinkedIn.