Gravel Driveway Math: The 2026 Guide to Cubic Yards, Tonnage, and Ordering the Right Amount
How gravel driveway math works: converting depth to cubic yards, the roughly 1.4 tons per cubic yard conversion, compaction and waste allowances, layered driveways, and ordering with a gravel calculator.
Gravel is sold by the ton, driveways are measured in feet, and depth lives in inches — which is why so many projects end with leftover stone or a delivery that quits eight feet from the garage. The bridge is short: area times depth gives cubic yards, and crushed stone converts at roughly 1.4 tons per cubic yard, plus compaction and honest waste on top. This guide walks the full chain — measuring, depth choice, the 324 divisor, density, the compaction allowance — then covers what arithmetic cannot see: layering against ruts, choosing stone sizes, surviving delivery day. A gravel driveway calculator at /gravel-driveway-calculator.html handles the conversions instantly, but the judgment calls are yours. Treat every figure here as a planning estimate; your supplier's scale ticket and local delivery minimums have the final say.
CHAPTER 01Volume First, Weight Second
Every gravel estimate starts as a volume problem, because the ground knows nothing about tons. You are filling a shallow prism: length times width times depth. The only trick is units, and the standard shortcut for imperial measurements is the 324 divisor — multiply your square footage by depth in inches, then divide by 324, and the result is cubic yards. The number works because one cubic yard spread one inch deep covers 324 square feet, which is just the yard-to-feet conversion (27 cubic feet per yard) with inches folded in.
So a 20-by-60-foot driveway — 1,200 square feet — at 4 inches deep is 1,200 times 4 divided by 324, about 14.8 cubic yards. Write that number down before thinking about tons, suppliers, or money, because volume is the quantity your site actually requires. Weight is a purchasing detail that depends on the material's density, and it comes next.
CHAPTER 02From Cubic Yards to Tons: The 1.4 Factor
Quarries sell crushed stone by weight, and the conversion factor is density: tons equal cubic yards times tons per cubic yard. Crushed limestone and similar aggregates run roughly 1.3 to 1.5 tons per cubic yard depending on the stone, the size mix, and moisture, and around 1.4 is the working number most estimators reach for. Our 14.8-cubic-yard example therefore converts to about 20.7 tons — call it 21 tons before allowances.
The factor is not fraud-proof precision; it is physics with a margin. A load of wet crusher run weighs more than the same volume of dry washed stone, and rounded decorative gravel sits differently in a bucket than angular crushed rock. Suppliers know their own product, so the professional move is to compute volume yourself, convert with 1.4 for budgeting, and confirm tonnage against the supplier's figure when you order. When the two disagree by more than about ten percent, ask what density they are using — it is a legitimate question that quarries answer without blinking.
CHAPTER 03Choosing Depth: What the Driveway Has to Carry
Depth is where driveways earn their longevity. A common residential recipe is 4 to 6 inches of compacted gravel for light car and SUV traffic on decent subsoil, 6 to 8 inches where heavy trucks, boats, or RVs will roll, and considerably more — sometimes 8 to 12 inches in layers — over soft clay or boggy ground. The depth carries the load down to the subgrade, so weak ground demands thicker structure, exactly the way a snowshoe works.
Resist the temptation to thin the order to save money, because thin gravel fails in the most annoying way: it does not fail all at once, it develops ruts and potholes in the wheel paths each spring, and the annual patching costs quietly exceed the original savings. Also account for what exists already — topping up an old driveway needs only the worn depth, while a fresh-cut path through soil needs the full section. Measure the actual low spots with a straightedge rather than trusting memory.
CHAPTER 04The Compaction and Waste Allowance
Here is the detail that separates accurate orders from short ones: gravel compacts. Loose stone dropped from a truck settles under traffic and rolling, typically consolidating by somewhere around 10 to 20 percent depending on the material and how hard it is compacted. If you order exactly the finished volume, the driveway ends up thin. Practical estimators either add that percentage to the order or, equivalently, order loose depth exceeding the compacted target.
Waste piles on top of compaction: spreading losses to the edges, stone pressed into soft mud at the entrance, a bit scraped off by the loader, and the undrivable last quarter-ton in the pile. A combined allowance of 10 to 20 percent over the calculated tonnage is the common hedge — our 21-ton example becomes an order of roughly 23 to 24 tons. Do not double-count, though: if you calculated from compacted depth, add the allowance once, and if your supplier prices partial loads oddly, rounding up to the next full ton is usually cheaper than a second delivery fee.
CHAPTER 05Building a Driveway in Layers
Quality gravel driveways are layered, not poured. The classic structure starts with larger angular base stone — the big, interlocking pieces often called crusher run or road base, which bind with fines to lock into a stable mass — followed by a middle lift of the same or slightly smaller material, finished with 2 to 4 inches of a smaller, cleaner stone like #57 for the driving surface. Each layer is spread and compacted before the next goes down, with the total section matching whatever depth your traffic and subgrade demanded.
The layering matters for your math in one specific way: calculate each layer by its own depth rather than averaging. A 1,200-square-foot driveway with 4 inches of compacted base plus 2 inches of finish stone is 14.8 cubic yards of base plus about 7.4 cubic yards of finish — roughly 21 and 10 tons respectively before allowances — and those two products usually come from different piles at different prices. Suppliers quote base and finish stone differently, and your budget should reflect that instead of discovering it on delivery day.
CHAPTER 06Stone Sizes, Costs, and Delivery Realities
Stone sizing jargon is numbered, and the numbers shrink as the stone gets bigger: #57 (around three-quarters inch to an inch) is the ubiquitous finish gravel; #4 and similar larger sizes serve as base and mud-relief layers; crusher run mixes fines with crushed faces and is the workhorse of driveways that need to lock. Angular stone always outperforms rounded pea gravel for driveways because the sharp faces interlock instead of rolling — pretty pea gravel is for paths, not parking.
Costs land in two parts: material and delivery. Regional prices for common aggregates often run somewhere in the tens of dollars per ton — call it 20 to 60 depending on where you live and what you choose — so our 21-to-24-ton order might land anywhere from a few hundred dollars to well over a thousand delivered. Trucks have practical limits too, commonly somewhere around 10 to 20+ tons depending on the rig and local road rules, so big orders may arrive in two loads with two spread fees. Price the whole truth at the supplier, then run your numbers at /gravel-driveway-calculator.html and compare.
CHAPTER 07Spreading, Grading, and Aftercare
Delivery day goes better with a plan: dump locations agreed in advance, a skid steer or tractor-line rental (or a very good wheelbarrow), and a grade that sheds water — a crowned driveway, higher in the middle, drains itself; a flat or bowl-shaped one collects the potholes you are trying to avoid. Spread in lifts of a few inches, compact each with a plate compactor or the tires of a loaded truck, and keep the crown consistent the whole length.
Aftercare is cheaper than rebuilding: fill potholes when they are small, refresh the finish layer every few years with a 1-to-2-inch top-dress (a small order by driveway standards), and keep edges edged so the stone stays where you spread it. A well-built gravel driveway is one of the cheapest per-foot surfaces you can own precisely because its maintenance is periodic rather than structural — and because you did the volume math once, correctly, with a calculator and a little compaction humility.
🔑 Key takeaways
- Volume first: square footage x depth in inches / 324 = cubic yards (1,200 sq ft at 4 inches is about 14.8 cubic yards).
- Convert with density: crushed stone runs roughly 1.4 tons per cubic yard (typically 1.3-1.5 depending on material and moisture).
- Add 10-20 percent for compaction and waste — compacted gravel settles, and short orders cost a second delivery fee.
- Match depth to traffic and subgrade: commonly 4-6 inches for cars, 6-8 for trucks and RVs, more over soft ground.
- Calculate layers separately — base and finish stone are different products at different prices.
- Angular crushed stone interlocks; rounded pea gravel rolls and belongs in paths, not driveways.
- Confirm the supplier's density and truck limits when ordering; the scale ticket is the final arbiter.
❓ Frequently asked questions
How many tons of gravel do I need for a driveway?
Compute cubic yards (square footage x depth in inches / 324), then multiply by about 1.4 tons per cubic yard, then add 10-20 percent for compaction and waste. A 1,200 sq ft driveway at 4 inches is about 14.8 cubic yards, roughly 21 tons, so an order of 23-24 tons is a sensible plan.
How many cubic yards are in a ton of gravel?
For typical crushed stone, one ton is roughly 0.7 cubic yards (the inverse of about 1.4 tons per yard). The exact figure depends on the stone — dense limestone runs heavier, lighter volcanic or slag aggregates run lighter — so use your supplier's stated density when precision matters.
How deep should a gravel driveway be?
Common residential guidance is 4-6 inches of compacted gravel for cars and light trucks on firm subsoil, 6-8 inches for heavy vehicles, and thicker layered sections over soft clay. Depth is the structure that carries load to the ground, so soft or wet soil deserves more, not less.
Do I need to order extra gravel for compaction?
Yes. Loose stone typically consolidates around 10-20 percent when compacted and trafficked, so ordering exactly the finished volume leaves the driveway thin. Add the allowance once, on top of a small waste margin, or order loose depth above your compacted target.
What is the difference between crusher run and #57 stone?
Crusher run is a mix of crushed stone and fines that compacts into a tight, load-bearing base — the workhorse for the layers under the surface. #57 is a washed, roughly three-quarter-inch stone with the fines removed; it drains well and makes a clean driving surface but does not lock like crusher run. Most good driveways use both, in that order.
How much does a gravel driveway cost?
Material for common aggregates often runs somewhere around 20-60 dollars per ton regionally, plus delivery. A 1,200 sq ft driveway at 4 inches needing roughly 21-24 tons might land anywhere from several hundred to over a thousand dollars depending on stone choice and haul distance. Get a per-ton delivered quote and multiply by your own tonnage estimate.
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