BuildMath

Gravel calculator

Enter the size of your area to see how much gravel to buy.

How much gravel do you need?

A 10 × 20 ft area at 4 inches deep needs about 2.47 cubic yards, or 3.46 tons, of typical gravel.

Measure the length and width in feet. Decide how thick the layer should be in inches. The calculator multiplies those sizes, converts cubic feet to cubic yards, then multiplies by density (1.40 tons per cubic yard unless you change it) so you can order by the yard or by the ton.

  1. Enter length and width. For a circular pad, open More options and switch the shape to Circle, then enter the diameter.
  2. Enter depth in inches. Four inches is a common driveway wearing course; two to three inches is enough for a path on a firm base.
  3. Confirm the material. Standard gravel, pea gravel, crushed stone, and sand use different typical weights.
  4. Open Estimate cost if you already have a quote per ton or per cubic yard.
  5. Order about 2.47 cubic yards (3.46 tons), or 134 bags (0.5 cu ft), for the default 10 × 20 ft driveway at 4 inches. The order line at the top follows the sizes you enter.

The formula is length × width × depth in feet, then divide by 27. Depth in inches divided by 12 becomes feet. Weight is cubic yards × tons per cubic yard. A 0.5 cubic foot bag is counted by dividing the cubic feet you need by 0.5 and rounding up.

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How much gravel do I need?

Multiply length by width by depth in feet, then divide by 27. A 10 × 20 ft driveway at 4 inches is 200 × (4 ÷ 12) ÷ 27 = 2.47 cubic yards. At 1.40 tons per cubic yard that is 3.46 tons.

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Worked example: 10 × 20 driveway at 4 inches

Worked example

Take a 10 ft by 20 ft driveway, 4 inches thick, with ordinary gravel at 1.40 tons per cubic yard and no extra waste.

10 × 20 = 200 square feet. Four inches is 4 ÷ 12 feet. 200 × 4 ÷ 12 = 66.67 cubic feet. 200 × 4 ÷ 12 ÷ 27 = 2.47 cubic yards. (200 × 4 ÷ 12 ÷ 27) × 1.40 = 3.46 tons. In 0.5 cubic foot bags that is 134 bags after rounding up.

That matches the default result on this page. If the ground is lumpy, add waste under More options so the tons-to-buy line goes up while the raw 2.47 yards stays visible.

One cubic yard at 4 inches covers 81 square feet, so this 200 square foot drive is a little under two and a half yards, not two.

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How far one cubic yard of gravel goes

DepthArea one cubic yard covers0.5 cu ft bags for 100 sq ft
2 in162 sq ft34 bags
3 in108 sq ft50 bags
4 in81 sq ft67 bags
6 in54 sq ft100 bags

These assume a level, even layer. Real driveways dish in the wheel tracks, so a 4 inch spec often needs a little extra at the edges.

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Questions

How much gravel do I need for a 10 × 20 driveway?
At 4 inches deep, 2.47 cubic yards, or 3.46 tons at 1.40 tons per cubic yard. Change the depth if your base is thicker, and add waste if the subgrade is uneven.
How many tons of gravel are in a cubic yard?
Typical dry gravel is about 1.40 short tons per cubic yard (2,800 lb). Some yards run 1.5 to 1.7 for wet or dense crushed stone. The tons line follows whatever density you enter.
How do I calculate yards of gravel?
Multiply length in feet by width in feet by depth in feet, then divide by 27. Convert inches of depth by dividing by 12 first. That cubic-yard figure is what most landscape yards want to hear.
Does #57 gravel change the calculator?
No. #57 is a size (about ¾ inch), not a different volume. Enter the same length, width, and depth. If your supplier’s #57 is heavier than 1.40 tons per yard, edit Custom density under More options.
How much area will one cubic yard of gravel cover?
About 162 square feet at 2 inches, 108 at 3 inches, 81 at 4 inches, and 54 at 6 inches. Coverage falls as the layer gets thicker. The table above is the same math the calculator uses.
Should I buy gravel by the ton or by the yard?
Match the unit on the quote. Quarries often sell by the ton; some landscape yards sell by the cubic yard. Switch the cost unit so the estimate uses the same quantity the invoice will.
How deep should a gravel driveway be?
Four to six inches of compacted gravel over a firm base is common for cars. Soft clay, frost, or heavier vehicles need a thicker section, sometimes with a separate base rock under the surface stone. Local soil matters more than a national rule.
How much extra should I add for a gravel base?
If you are placing a wearing course over a new base, calculate each layer on its own depth. A 4 inch surface plus a 4 inch base is two separate 2.47 yard loads on a 10 × 20 drive, not one. Use waste of 5 to 10 percent when the trench is irregular.
How do I calculate gravel for a driveway?
Multiply length in feet by width in feet by depth in feet, then divide by 27. A 10 × 20 ft driveway at 4 inches is 2.47 cubic yards, or 3.46 tons at 1.40 tons per cubic yard.
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Written by The BuildMath team. Formulas tested against worked examples. Updated October 21, 2026.