The Formula Behind This Calculator
Volume (cu ft) = length x width x (depth in inches / 12)
Cubic yards in place = volume (cu ft) / 27
Order volume = cubic yards in place x 1.15 (compaction and settling allowance)
Tons = order volume x tons per cubic yard for the stone type
Gravel is bought by weight and placed by volume, so every estimate is a conversion. The geometric part is simple: area times depth, turned into cubic yards. The judgment part is the density, which is why the stone type is an input rather than a hidden constant. Angular crushed stone packs tight and heavy, round river rock leaves more air between stones and weighs less per yard, and the 15 percent allowance covers the difference between the loose pile that arrives and the compacted layer you measured for. Skip that allowance and a 4 inch layer quietly becomes a 3.4 inch layer spread over the same ground.
Worked Example: A 20 by 10 Parking Pad, 4 Inches of Crushed Stone
You are topping a parking pad of 20 feet by 10 feet with one 4 inch layer of crushed stone at 1.40 tons per cubic yard.
- Volume: 20 x 10 x (4 / 12) = 66.7 cubic feet.
- Cubic yards in place: 66.7 / 27 = 2.47 cubic yards.
- Order volume with the 15 percent allowance: 2.47 x 1.15 = 2.84 cubic yards.
- Tons: 2.84 x 1.40 = 3.98, so order 4 tons.
- In bags it would take about 154 bags of 0.5 cubic feet, which is the clearest possible argument for a bulk load.
- Budget: 4 tons at $30 to $55 per ton is $120 to $220 of stone, plus a delivery fee, in October 2026 regional pricing.
If this pad is a full driveway build rather than a top layer, run the calculator twice more: once for a 4 to 6 inch coarse base layer and once for the middle layer, then add the three orders. Suppliers combine layers into one delivery only if the stones are the same, so most driveway builds take two deliveries, base first.
A Complete Guide to Estimating Gravel and Crushed Stone
Gravel projects look foolproof until the truck leaves and the pile turns out to be half the job, or twice it. The mistakes are almost never in the multiplication. They are in the depth you forgot to compact, the stone density you assumed, and the soft soil that swallows the first layer. This guide covers those three traps and the layering logic that makes a gravel surface last.
Layers: How Real Bases Are Built
A lasting gravel surface is a sandwich. Over shaped and compacted soil (and a geotextile fabric on clay) goes a base of large angular stone, 1 to 2 inch pieces that bridge soft spots and drain freely. Over that goes a middle layer of 3/4 inch stone that chokes the voids in the base. The top layer is the fine, angular material with stone dust that packs into a surface you can walk, sweep and plow. Each layer gets compacted before the next lands. Estimate each layer with this calculator using its own depth and stone type, and resist the shortcut of one deep layer of a single stone: it ruts, migrates and never packs as hard as the layered build.
Compaction and the Vanishing Quarter
Loose stone is full of air. A plate compactor or a few passes of a vehicle tire collapse those voids, and the layer typically loses about 20 to 25 percent of its loose thickness. That is why a load figured to the exact geometric volume always finishes thin. The 15 percent order allowance in this calculator, combined with measuring your depth as the compacted target, splits the difference sensibly for homeowner equipment. If you are compacting with a rented plate compactor in proper lifts, you can trim the allowance mentally toward 10 percent. If you are spreading and driving on it, keep the full 15 and expect a small leftover pile, which every gravel owner ends up grateful for when the first pothole appears.
What Gravel Costs in 2026
As of October 2026, bulk crushed stone and gravel commonly run $30 to $55 per ton at the yard in most regions, with river rock and decorative stone at $55 to $90 per ton and decomposed granite varying widely by region. Delivery adds roughly $50 to $100 per load within a normal radius, and trucks typically carry 8 to 15 tons, so splitting an order with a neighbor is a legitimate strategy. Bagged stone at home centers runs about $4 to $6 per 0.5 cubic foot bag, which works out to several hundred dollars per ton: bags are for repairs and tiny jobs only. For the 4 ton example above, expect about $170 to $320 all in with delivery, against well over $600 in bags.
Delivery Day and Spreading Habits
- Have the driver dump on a tarp or on the driveway itself, never on lawn you care about: stone migrates into soil permanently.
- Spread with a hard rake, working from the pile outward, and check depth with a marked stick in several places.
- Compact in lifts of about 2 inches if you have a plate compactor, wetting dusty stone lightly to help it bind.
- Crown driveways slightly at the center, about 1 inch over a 10 foot width, so water sheds instead of ponding and potholing.
- Keep the leftover half ton in a back corner pile. Gravel surfaces need small top ups, and matching stone later is harder than it sounds.