Gravel Calculators
Gravel driveway guide
A gravel driveway is cheap to build and easy to fix — if it's built as layers with drainage, not a pile of stone on dirt. This is the whole playbook: layers, depths, materials, edges, and the maintenance rhythm. Before ordering, estimate your gravel quantity — the layers below explain why depths change the total.
Sources and method: the formulas and density figures used here are the site's standard values, documented on the methodology page together with the hand-calculated test cases.
The anatomy: three parts
- Subgrade — the shaped ground itself, stripped of topsoil, crowned toward the edges, sloped so water exits somewhere useful.
- Base layer — 4–6" of dense-graded crushed stone (crusher run / road base), compacted in lifts. This is the structure.
- Top layer — 2–3" of clean angular stone (#57 or #67). Drains, sheds water, and can be raked level when it ruts.
Depth by use
| Use | Base | Top |
|---|---|---|
| Cars only | 4" | 2–3" |
| Cars + trucks | 5–6" | 3" |
| Heavy / soft ground | 6–8" (+ #1–#4 stone sub-base) | 3" |
Choosing the stone
Base: angular with fines — crusher run, dense-graded base, or your state's equivalent spec — because fines lock the layer into something truckproof. Top: washed angular stone (#57/#67) that drains and stays put. Never: pea gravel or river rock on anything driven — round stone rolls, ruts, and scatters. The full code-by-code reference lives in gravel types and sizes explained.
Details that decide whether it lasts
- Crown and slope: center 2–3" above edges so water runs off, never pools. Water is the enemy; standing water is a pothole factory.
- Compaction: plate compactor in 2–3" lifts on the base. Compaction is what turns loose stone into pavement.
- Geotextile fabric: on soft ground, one layer under the base stops stone migrating into mud — the cheapest insurance in this whole guide.
- Edging or borders: keep the top layer where it belongs; gravel spreads sideways without a constraint.
- Drainage: where water crosses the drive, a culvert or a French drain — not a hope.
Maintenance rhythm
Expect to rake, fill potholes, and re-dress the surface every year or two — a few tons of #57 spread into ruts, re-crowned. Every 5–10 years a full regrade. That's the honest cost of gravel: far cheaper to build than paving, and it asks for a little attention in return. Narrow side-yard runs use the same materials at walkway scale, see the gravel walkway calculator.
Worked example: a single-car driveway
Take a plain 12 × 20 ft parking pad — 240 ft². The base at 4 inches of crusher run is 240 × ⅓ ft = 80 ft³ = 2.96 yd³, which at 1.60 t/yd³ is 4.74 tons. The top at 2 inches of #67 stone is 40 ft³ = 1.48 yd³, which at 1.37 t/yd³ is 2.03 tons. Total: about 6.8 tons — order about 7.5 tons: the base is a compacted layer (add 10–15% to its 4.74 tons), the top a loose surface layer (add 5–10% to its 2.03 tons). Notice what drives the total: the base is more than two-thirds of the weight, and one extra inch of base across the same pad adds about 1.2 tons. Depth, not area, is where driveway estimates go wrong.
Do the math
Two tools, one question each: how much gravel does my driveway need (two-layer quantities), and what will it cost (the same layers at your supplier's rates). Refreshing only? The driveway calculator skips the base layer for resurfacing runs.
This guide is part of more gravel guides on this site.