Gravel Calculator: How Much Gravel Do You Need?

How do you calculate how much gravel you need?

Measure the area and decide on a depth. Turn the depth into feet first (3 inches is 0.25 ft), then multiply length x width x depth. That gives cubic feet. There are 27 cubic feet in a cubic yard (3 x 3 x 3), so divide by 27. For a round area, such as a tree ring or a round planter, the area is 3.1416 x radius x radius.

Landscape yards sell gravel by the cubic yard or by the ton, and garden centers sell it in bags. The calculator gives all three, plus cubic meters if you work in metric.

How many tons is a cubic yard of gravel?

Usually 1.3 to 1.45 US tons (2,600 to 2,900 lb) for loose stone as delivered. Rounded stone such as pea gravel and river rock leaves more air between the pieces, so it sits near 1.35 tons. Angular crushed stone packs a little tighter, around 1.4, and crusher run with fines in it is heavier again, about 1.45. Lava rock is full of holes and weighs about half as much, around 0.7 tons per yard.

Published figures for the same stone differ by up to about 17%, and wet stone weighs more than dry. If your supplier quotes its own weight per yard, pick Custom and enter that number.

How much gravel do you need for a balcony, patio, or path?

Small jobs are where bags beat a delivery. A pea gravel top layer on balcony planters, a drainage layer under pots, a gravel strip along a ground-floor patio, or a short path to a bin store usually comes to a few cubic feet, not yards. Check your lease or building rules before you put loose stone on a balcony, and remember weight: 0.5 cu ft of pea gravel is about 50 lb.

Depth matters more than people expect. Small rounded pea gravel is often laid as little as 1.5 inches deep in a decorative bed, while larger river rock is usually laid 2 to 3 inches deep to cover the ground. A walking path or a base for pavers needs more, and compacted base shrinks, so tick the 10% extra box for those.

Worked example: a patio, a tree ring, and a balcony planter strip

Patio, 12 x 10 ft, 3 inches deep, #57 crushed stone: 12 x 10 x 0.25 = 30 cubic feet. 30 / 27 = 1.11 cubic yards, or 0.85 cubic meters. 1.11 x 1.4 = about 1.56 tons. In bags, 30 / 0.5 = 60 bags of 0.5 cu ft. At this size a bulk delivery is usually easier than 60 bags.

Round tree ring, 4 ft across, 2 inches deep, pea gravel: 3.1416 x 2 x 2 x (2 / 12) = 2.09 cubic feet, so 5 bags of 0.5 cu ft (4.19 rounded up).

Balcony planter strip in metric, 3 m x 0.6 m, 5 cm deep: 3 x 0.6 x 0.05 = 0.09 cubic meters, which is 3.18 cubic feet. That is 7 bags, or about 0.16 US tons (roughly 320 lb) of pea gravel spread over the strip.

Should you buy gravel in bags or in bulk?

A standard bag of all-purpose gravel, such as QUIKRETE No. 1151, is 50 lb and yields about 0.5 cubic feet, so 54 bags fill one cubic yard. For planters, a balcony, or a short path, bags are simpler: no truck, no pile on the sidewalk, and you can carry them up in the lift. Past roughly half a yard, compare a bulk price, because a yard of loose stone is usually far cheaper than 54 bags.

How much gravel do you need for a fish tank?

About 1 lb of gravel per gallon for each inch of depth is the usual rule of thumb, so a 20 gallon tank takes about 20 lb for a 1 inch bed and 40 lb for 2 inches. For a closer number, use the fish tank calculator above: it multiplies the tank floor by the depth instead of going by gallons.

The math: inside length x width x depth in inches gives cubic inches. Divide by 1,728 to get cubic feet, then multiply by about 100 lb per cubic foot for aquarium gravel (sand runs a little heavier). A 20 gallon long tank, 30 x 12 inches, at 2 inches deep is 720 cubic inches, 0.42 cubic feet, or about 42 lb. A 20 gallon high, 24 x 12 inches, needs only about 33 lb for the same depth because its floor is smaller.

The rule of thumb runs high on tall tanks. A 55 gallon tank is usually 48 x 13 inches, so a 2 inch bed is about 72 lb, not the 110 lb the per-gallon rule suggests. Most freshwater tanks use 1 to 2 inches; planted tanks often go deeper.

How much gravel do you need for a driveway?

A single-car gravel driveway of about 12 x 25 ft needs roughly 3.7 cubic yards, or about 5.4 tons of crusher run, for every 4 inches of depth. Tap the driveway preset to load those numbers with the 10% extra switched on, then change the size to match yours.

HomeGuide’s cost guide gives 4 to 8 inches as the usual depth for a single-car gravel driveway. New driveways are normally built in layers, with a base layer under a finer top layer, so run the calculator once for each layer at its own depth and stone type, then add the results together. Soft or wet ground may need more depth, and a local supplier or contractor can tell you what works on your soil.

How do you work out what gravel will cost?

Multiply the tons by the price per ton, or the cubic yards by the price per yard. Type your supplier’s price into the optional price box and pick which unit it is quoted in, and the calculator shows the total for the stone.

As a rough guide, HomeGuide’s 2026 cost guide puts bulk gravel and crushed stone at about $10 to $50 per ton, or $15 to $75 per cubic yard, on average, with small quantities often costing more than $100 per ton. Decorative stone and delivery can add a lot, so treat that range as a starting point and use a local quote for the real number.