1. Measuring area
When you tap the corners of your driveway, we store the outline as latitude and longitude points and calculate its geodesic area, which accounts for the curve of the earth (it matters for long rural drives). We subtract any areas you cut out and show the result rounded to the nearest 10 square feet. If you type in measurements instead, we add up your rectangles.
Accuracy. Satellite measurements are usually within a few percent. Trees, shadows, and new construction can throw them off. The imagery may be months or years old, so if your driveway has changed, drag the corners or type it in.
2. Choosing a depth
You answer three questions: what the project is, what's there now, and how it'll be used. We look up a recommended depth and two alternatives, and show a one-sentence reason with each.
| Project | What's there now | Use | We recommend | Options |
|---|---|---|---|---|
| New driveway | Dirt or grass | Cars | 4 in (two lifts if deeper) | 3, 4, 6 |
| New driveway | Dirt or grass | Trucks, heavy | 6 in | 4, 6, 8 |
| Refresh | Thin old gravel | Cars | 2 in | 1.5, 2, 3 |
| Refresh | Solid old gravel | Just cover it | 1.5 in | 1, 1.5, 2 |
| Parking pad | Anything | Cars | 4 in | 3, 4, 6 |
| Path or walkway | Anything | Foot traffic | 2 in | 1.5, 2, 3 |
| Over concrete or asphalt | Hard surface | Any | 2 in (it will migrate) | 1.5, 2, 3 |
The recommendation is a default, never a lock. Pick any depth and the numbers update. These are the depths for the gravel you're ordering now. Building a new driveway from bare ground with a separate base course is a bigger job; see Hello Gravel's driveway depth guide.
We review this table against real outcomes. When a customer who measured with us later says they didn't have enough, or had plenty, that feeds back into the defaults.
3. From cubic yards to tons
- Cubic yards = area (sq ft) x depth (ft) / 27.
- Tons = cubic yards x density. Driveway gravel is about 1.4 tons per cubic yard; road base about 1.5. We store density per product and show the one we used.
- Compaction. Road base and crusher run pack down 15 to 20 percent. When the material compacts, we add that and say so.
- Buffer. We suggest 10 percent extra and show it as a separate toggle, never baked into the headline number.
- Truckloads. A standard tandem dump truck carries about 18 tons (it varies by market). If you're within 20 percent of a full truck, we'll point it out.
Displayed tons are rounded to the nearest half ton; exact tons are used for pricing.
The Driveway Size Report
The Driveway Size Report summarizes the size of driveways measured by Hello Gravel customers.
- Source. Driveway dimensions customers gave us while ordering. It does not use outlines traced on map imagery.
- Cleaning. We drop duplicates, test entries, and obvious typos (for example, under 50 or over 50,000 square feet).
- Privacy. We never publish addresses, coordinates, or anything that identifies a home. Groups with fewer than 25 driveways aren't shown.
- Updates. Monthly. Each version shows its sample size and date.
- Reuse. The summary table is free to reuse under CC BY 4.0 with credit to Measure The Driveway and a link.
Engine version
The math above runs in one shared engine used by the website, the iPhone app, and Hello Gravel's team. Current version: 1.0.0.