How do I calculate how much rock I need?

Multiply length by width in feet to get square feet, multiply by depth in inches divided by 12 to get cubic feet, and divide by 27 for cubic yards. Multiply cubic yards by about 1.4 to get tons for most crushed rock, or 1.35 for rounded river rock.

How much area does a ton of rock cover?

A ton of crushed rock covers about 100 square feet at 2 inches deep, 70 square feet at 3 inches, and 50 square feet at 4 inches. Larger decorative rock needs more depth, so a ton of 2 to 4 inch river rock covers only 40 to 60 square feet.

How many tons are in a yard of rock?

Between 1.3 and 1.5 tons. Base rock with fines is heaviest at about 1.5 tons per yard, crushed 3/4 inch rock is about 1.4, and rounded river rock about 1.35. Lava rock is the exception at roughly half a ton per yard.

What is the cheapest landscape rock?

Crushed base rock and crushed limestone, at $22 to $50 per ton, are the cheapest. Pea gravel is next. River rock, marble chips, and polished beach pebbles cost several times more per ton.

Should I buy rock by the ton or by the yard?

Buy whichever unit your supplier sells in, but compare prices per ton. A price per yard looks cheaper because a yard of rock weighs about 1.4 tons. Divide a per-yard price by 1.4 to compare it with a per-ton quote.

Landscaping

Rock Calculator

Use this rock calculator for any job measured in rock rather than gravel: base rock under a slab, drain rock in a trench, river rock in a bed, or decorative crushed granite. Enter the area and depth, choose a rock type, and get cubic yards, tons, the area a ton will cover, and a delivered cost range.

What you'll need

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Prices as of Sep 25, 2026, 6:18 PM UTC. Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon.com at the time of purchase will apply to the purchase of this product.

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Frequently asked questions

How do I calculate how much rock I need?: Multiply length by width in feet to get square feet, multiply by depth in inches divided by 12 to get cubic feet, and divide by 27 for cubic yards. Multiply cubic yards by about 1.4 to get tons for most crushed rock, or 1.35 for rounded river rock.
How much area does a ton of rock cover?: A ton of crushed rock covers about 100 square feet at 2 inches deep, 70 square feet at 3 inches, and 50 square feet at 4 inches. Larger decorative rock needs more depth, so a ton of 2 to 4 inch river rock covers only 40 to 60 square feet.
How many tons are in a yard of rock?: Between 1.3 and 1.5 tons. Base rock with fines is heaviest at about 1.5 tons per yard, crushed 3/4 inch rock is about 1.4, and rounded river rock about 1.35. Lava rock is the exception at roughly half a ton per yard.
What is the cheapest landscape rock?: Crushed base rock and crushed limestone, at $22 to $50 per ton, are the cheapest. Pea gravel is next. River rock, marble chips, and polished beach pebbles cost several times more per ton.
Should I buy rock by the ton or by the yard?: Buy whichever unit your supplier sells in, but compare prices per ton. A price per yard looks cheaper because a yard of rock weighs about 1.4 tons. Divide a per-yard price by 1.4 to compare it with a per-ton quote.