Gravel Calculator – How Much Gravel Do I Need?

Fast and frugal. Plain HTML, CSS, and JavaScript — no frameworks, no sign-up, no popups. It works on a slow phone at the supply yard.

Private by design. Every calculation runs entirely in your browser. The dimensions you enter are never sent to a server, logged, or shared — the site has no backend to send them to.

Shows its work. Every result displays the formula and the density figure it used, so you can check the math yourself — and the methodology page publishes hand-calculated test cases you can reproduce.

Honest about limits. An estimate is an estimate. Compaction, moisture, uneven ground, and supplier rounding mean real orders differ from calculated figures — the tools say so plainly instead of pretending otherwise.

Last updated: 7 November 2026 · Report an error

Gravel quantity comes down to two simple formulas:

Volume = Length × Width × Depth
Weight = Volume × Material Density

The area depends on the shape: rectangles use length × width, circles use π × radius², and triangles use ½ × base × height. Depth must be converted to the same unit — 3 inches is 0.25 feet. Cubic feet divide by 27 to give cubic yards, and cubic yards multiply by the material's density to give tons.

1. Measure the length, width, and the depth of gravel you want to spread.
2. Convert the depth to feet and multiply: area × depth = cubic feet; ÷ 27 = cubic yards.
3. Weigh it: cubic yards × the material's density in tons per cubic yard = tons. Bags are cubic feet ÷ 0.5.

Allow for the real world. This calculator gives the loose, uncompacted quantity. Crushed stone bases typically compact by about 10–15%, so ordering 5–10% more than the calculated amount is common practice — and suppliers usually deliver in rounded load sizes anyway.

Worked example: a 20 × 10 ft bed at 3 inches deep is 200 ft² × 0.25 ft = 50 ft³, which is 1.85 yd³; at gravel's 1.42 tons per cubic yard that is 2.62 tons — or exactly 100 of the standard 0.5 ft³ bags, which is the point where bulk delivery almost always beats bags on price.

Mixing rather than spreading? The same volume math splits into ingredients in the concrete mix ratio calculator (cement, sand, and gravel by ratio) and the sand and gravel mix calculator for two-material blends.

Densities below are the typical loose (uncompacted) figures the calculator itself uses. Gravel generally weighs roughly 1.4–1.7 tons per cubic yard depending on type and compaction — always confirm with your supplier, since gradation and moisture change the number.

Price your result with the gravel cost calculator, or convert any figure with the yards-to-tons converter. Densities are loose, dry values — the same ones every tool on this site uses.