Gravel Calculator
Driveway, drain bed, or path: yards and tons in seconds
What is gravel calculator?
A gravel calculator answers two questions: how many cubic yards (or tons) do I need, and how does that map to a delivery order. The volume math is straightforward — area times depth — but landscape suppliers price by weight, and the conversion catches a lot of homeowners off guard.
The default density is 100 lb/ft³, which is the standard for general-purpose washed gravel and most decorative landscape stone. Heavier crushed limestone or basalt can run 110-120 lb/ft³, so call your supplier if you need precision; loose pea gravel is lighter, around 95 lb/ft³.
What depth to choose? Four inches is the textbook minimum for a residential driveway base. Two inches is the standard for paver bedding under bedding sand. Two to three inches works for paths and walkways. For a French drain or drainage pit, depth depends on outflow grade — usually 8-12 inches.
Bulk vs bagged: at landscape supply yards, bulk gravel typically runs ~$25-50 per ton delivered. A 50-lb bag at the home center is roughly 0.5 cubic feet — more than 50 bags equals about a yard. By the time you’re past 2 cubic yards, bulk wins on price and saves a half-dozen trips to the truck.
The 10% waste factor default covers spread loss, edge slip, and the inevitable scoop-too-much. Bump to 15% for narrow trench work where gravel ends up in the surrounding soil. Compaction is a separate concern: if your spec is for a 4-inch finished base, order enough to lay about 5 inches loose, since gravel compresses roughly 20-25% when tamped.
When to use a gravel calculator
- Driveway base prep — Lay 4 inches of compacted gravel under a new driveway. Enter the run length and width to get cubic yards and tons for the delivery order.
- Drain bed under a downspout — A 3 ft x 6 ft drainage pit at 12 in deep takes a surprising amount of gravel. The calculator handles uneven cross-sections by depth.
- Paver patio sub-base — 2 inches of gravel under bedding sand stabilizes any patio. Output in tons matches landscape-supply pricing.
How to use the Gravel Calculator
- Measure the area — For rectangular driveways and pads, multiply length by width. For drain trenches, length by trench width. Break L-shapes into rectangles and add results.
- Pick a depth — Use 4 inches for a driveway base, 2 inches for a paver bed, 2-3 inches for a path or walkway. Compacted gravel adds about 25% on top of loose material.
- Read the tonnage — Bulk gravel is sold by weight at most yards. Output shows tons (1 cu yd of gravel weighs roughly 1.35 tons at the default density).
- Apply waste factor — 10% covers spread, edge slip, and compaction allowance. Bump to 15% for trench work where some gravel ends up in the surrounding fill.
Worked examples
20 ft x 100 ft driveway at 4 in
Input: 20 ft x 100 ft x 4 in depth
Output: 24.7 cu yd / 33.4 tons (with 10% waste)French drain trench
Input: 1 ft x 30 ft x 12 in depth
Output: 1.22 cu yd / 1.65 tonsWrap drainage gravel in landscape fabric to keep silt out.
10 ft x 12 ft paver pad at 2 in
Input: 10 ft x 12 ft x 2 in depth
Output: 0.81 cu yd / 1.10 tons