Gravel calculator

This gravel calculator covers the loose materials of a landscaping or driveway job: pea gravel for paths, #57 crushed stone for drainage, crusher run or road base under pavers and driveways, river rock for beds, decomposed granite for patios, sand for paver bedding, and topsoil for lawns.

Landscape yards sell by the cubic yard or the ton, and home centers sell bags. So you get all three:

• cubic yards to order, including compaction and extra;
• weight in tons, from the material's loose bulk density;
• number of bags at the bag size you choose.

The area can be a rectangle, a circle (a tree ring or round bed), a triangle, or a known square footage. Switch between US units and metric at the top. The material list has editable prices that your browser remembers, and you can export it to PDF or Excel. No sign-up, and nothing leaves your browser.

The math has three steps.

1. Finished volume = area × depth. In US units: square feet × depth in inches ÷ 12 = cubic feet; cubic feet ÷ 27 = cubic yards.
2. Volume to order = finished volume × (1 + compaction) × (1 + extra). Compaction covers base materials that shrink when tamped; extra covers spillage and uneven ground.
3. Weight = volume to order × bulk density.

Default loose densities (edit them under Material properties):

• pea gravel ≈ 1.4 tons per cubic yard;
• #57 crushed stone and river rock ≈ 1.35 tons per yard;
• crusher run / road base ≈ 1.5 tons per yard;
• sand ≈ 1.3 tons per yard;
• topsoil ≈ 1.05 tons per yard.

Wet material weighs more. Your supplier's tons-per-yard figure is the one to trust.

1. Pea gravel path or patio. 20 × 10 ft = 200 sq ft at 3 in deep, 5% extra:

• finished volume 200 × 3/12 = 50 cu ft = 1.85 yd³;
• to order 50 × 1.05 = 52.5 cu ft = 1.94 yd³;
• weight about 2.7 tons;
• in 0.5 cu ft bags that would be 105 bags, which is why bulk delivery usually wins above about one yard.

2. Road base under a shed or parking pad. 12 × 24 ft at 4 in compacted, 20% compaction, 5% extra:

• finished volume 96 cu ft;
• to order 96 × 1.2 × 1.05 = 121 cu ft = 4.48 yd³;
• weight about 6.7 tons. Order only 3.6 yd³ and the compacted layer ends up closer to 3 in than 4.

3. Topsoil for a new lawn. 400 sq ft at 4 in with 15% settling and 5% extra: 5.96 yd³, about 6.3 tons.

Depth depends on what the gravel has to carry. Typical figures:

• decorative stone in beds: 2–3 in over landscape fabric;
• walkways: 2–3 in of pea gravel or DG, ideally over 2–4 in of compacted base;
• paver patios: 4–6 in of compacted base plus 1 in of bedding sand;
• gravel driveways: 4–6 in of compacted base and 2–3 in of surface stone; more on soft clay;
• lawn topsoil: 4–6 in, allowing for settling.

The calculator works with the finished depth and adds compaction as a separate percentage. For a driveway that carries trucks, or a base under a structure, follow your designer or local code.

Bags are handy for small jobs under about half a yard, but per cubic yard they usually cost several times more than bulk. Bulk delivery adds a truck fee, and many yards have a minimum load, so order everything in one trip.

• Round up. A short half-yard means a second delivery fee.
• Ask the yard for its tons-per-yard figure and enter it, so the weight is right for quarry-specific stone.
• Plan the drop spot. A dump truck leaves one pile; keep it close to the job and off the lawn if you can.
• Lay landscape fabric under decorative gravel; the material list adds it for you.