How Much Gravel Do You Need for a Driveway? A Durham Homeowner's Calculator Guide

People call me all the time already halfway into a gravel project, standing in the driveway with a tape measure, trying to figure out how much to order. It's the single most common question I get before a job. Order too little and you're paying a second delivery fee while the truck loops back around. Order too much and there's a pile of crusher run sitting in the yard for a month, in everybody's way.

So here's how I actually run the math on a Durham driveway, step by step, so you can do it yourself with a tape measure. I've been quoting gravel jobs across Durham, Cary, Chapel Hill, Hillsborough, and Mebane for years, and the estimating part isn't complicated once you know the two numbers that trip everyone up: depth and compaction.

The short version

Gravel is sold two ways. Quarries and haulers price it by the ton. Contractors and plans talk in cubic yards. You need to move between the two, then add a bit extra because gravel shrinks when it packs down. Get those three things right and you're basically done.

Here's the sequence:

• Square footage. Length times width, in feet.

• Depth. How many inches of stone you're laying.

• Cubic yards. Square feet times depth-in-feet, divided by 27.

• Tons. Cubic yards times the material weight (crusher run is about 1.5 tons a yard).

• Add 10 to 20 percent for compaction and the gravel that scatters off the edges.

Here's a shortcut worth memorizing: a ton of gravel covers roughly 100 square feet at 2 inches deep, about 50 square feet at 4 inches, and around 33 square feet at 6 inches. So a plain 12-by-40 drive at 4 inches (480 square feet) works out around 10 tons once you add the compaction buffer, which is still under a single truckload. If your gut said "a couple truckloads," your gut was ordering too much.

Worked all the way through, a 12-by-40 driveway at 4 inches goes like this: 480 square feet times 0.33 feet of depth is about 160 cubic feet, divided by 27 is roughly 6 cubic yards. Times 1.5 tons a yard for crusher run is about 9 tons, then add 15 percent and you're near 10. That's the whole calculation, and you can run it on any size drive with a tape measure and the numbers above.

The mistake that costs people a second delivery

Compaction. This is the one nobody accounts for, and it's the reason a driveway that looked full on delivery day is thin and rutted by the first wet spring.

Crusher run loses 15 to 20 percent of its loose volume when it packs down under a plate compactor and daily traffic. That angular mix of stone and fines is exactly what makes it a good driveway base, and it's also why an 8-inch dump of it never densifies properly at depth. It has to go down in 2- to 4-inch lifts, each one compacted before the next. A single deep pile will rut and pothole its first season. So whatever your bare math says, you order more.

Durham dirt matters here. A lot of our soil around the Triangle is heavy red clay. Clay holds water and swallows gravel if you lay stone straight onto soft subgrade. On those sites we strip the topsoil to firm ground and often put down a geotextile fabric first, so the new gravel doesn't disappear into the mud over the next couple of winters. If your existing drive already looks like it's turning back into a dirt road, that's usually what happened underneath.

How deep, and how many layers

Depth depends on what the driveway carries and whether you're starting from scratch.

Situation	Depth	Build
Refreshing the surface	3–4 in	One surface course of crusher run or #57
New drive, light use	6 in	Compacted crusher-run base, single course
New drive over bare ground	6–8 in	4-in crusher-run base + 2-in #57 surface, layered
Farm road / RV or equipment pad	8 in+	Deeper base, often over fabric on clay

A new driveway is really two or three orders stacked. If you're building from raw dirt, run the math once for the base layer and once for the surface layer, then add them together. Pricing only the top course is how people end up short.

Which gravel for a Triangle driveway

Three come up most often around here:

• Crusher run is the base I reach for on nearly every drive. The fines pack tight into a firm, load-bearing surface, and it's the cheapest per ton. On our clay it holds up where looser stone won't.

• #57 stone is a clean, no-fines stone about three-quarters of an inch. It drains fast and looks sharp, so it's a common top layer. It won't lock up into a hard surface on its own, though, so it goes over a compacted base, not straight on dirt.

• Pea gravel looks nice but shifts and ruts under tires. On a driveway I'd only use it as a surface over a solid base, if at all.

Turning it into truckloads

Once you have your tonnage, delivery is simple. A standard tandem dump truck hauls about 15 to 16 tons. That single 12-by-40 driveway sits well under one load. A long farm road or a new build with a full base and surface can run two loads or more. Ordering a full truck usually gets you a better per-ton rate, so if your number lands close to a full load, rounding up a little can be the cheaper move.

Common questions

How much gravel do I need for a 2-car driveway?

A two-car drive around 20 by 20 feet takes roughly 8 tons at a 4-inch depth once you allow for compaction. If you're building new over bare soil, plan for more, since you're laying a base plus a surface rather than one thin layer.

How many tons are in a truckload of gravel?

A standard tandem dump truck carries about 15 to 16 tons. Smaller trucks carry less. A full load usually comes with a better per-ton price.

What's the best gravel for a driveway in North Carolina?

Crusher run for the base, because the fines pack into a firm surface in our clay soil. Many homeowners top it with #57 stone for looks and drainage. Skip pea gravel as a standalone surface here.

How deep should a gravel driveway be?

About 6 to 8 inches of total gravel for a new drive over raw ground, built in layers. A resurface or top-up is usually 3 to 4 inches.

Do I need a permit for a gravel driveway in Durham?

For a straightforward residential driveway on your own property, usually not. It can change if you're adding a new connection to a public road or working in a regulated area, so it's worth a quick check with the county before a bigger project. We're happy to point you in the right direction when we come out.

Hunter Excavating installs, repairs, and resurfaces gravel driveways and builds outdoor drainage across Durham, Raleigh, Cary, Chapel Hill, Hillsborough, Mebane, and the surrounding Triangle. If standing water or a washed-out drive is the real problem, our grading and drainage work usually matters more than the stone on top.