How to Calculate How Much Gravel You Need
Gravel is usually measured by volume for the project area and sold either by weight, bulk volume or bags. GravelScope calculates the project volume first, then uses the selected bulk density to estimate weight.
What Gravel Depth Should You Use for Driveways and Paths?
The correct depth depends on the material and the job. Decorative landscape gravel may use a relatively shallow layer, while driveways and load-bearing bases often need deeper, compacted layers and sometimes multiple materials.
| Project | Planning range | What to check |
|---|---|---|
| Decorative gravel | About 2–3 in | Stone size, weed membrane and desired coverage |
| Garden paths | About 2–4 in | Foot traffic, edging and base condition |
| Driveway surface | About 3–4+ in | Vehicle load, sub-base, drainage and compaction |
| Base layer | Project-specific | Local construction requirements and engineer/contractor guidance |
These are general planning ranges, not engineering specifications. Local soil conditions, drainage and load requirements can change the correct depth.
Why Tons and Cubic Yards Can Differ
A cubic yard measures volume; a ton measures weight. The same cubic-yard volume can weigh differently depending on the gravel type, particle size, moisture and how tightly the material is packed. That is why GravelScope shows both volume and estimated weight instead of using one fixed “yards-to-tons” conversion for every material.
How Much Gravel Should You Order?
Often you should order extra gravel beyond your calculated amount. Real projects can lose material to uneven ground, settlement, compaction, spreading and measurement error. The calculator starts with a 10% allowance, but you can change it to match your project. For a large or structural job, ask the supplier or contractor what allowance they recommend.
Worked example
Suppose a rectangular area is 20 ft long and 10 ft wide with a 2 in gravel layer. The base volume is about 33.3 cubic feet. Adding a 10% allowance gives about 36.7 cubic feet, or about 1.36 cubic yards. The weight then depends on the selected bulk density.
This is why changing the gravel type in the calculator can change the tonnage without changing the project dimensions.
Quick Gravel Calculators by Size
Calculate gravel for common project sizes and applications. Get instant estimates for cubic yards, tons, and bags.
Gravel Planning Guides
Use these practical guides to check the assumptions behind your estimate before ordering material.
Complete 10x10 gravel calculator with cubic yards, tons and bags.
DepthHow deep should gravel be?Planning ranges for decorative gravel, paths, driveways and base layers.
WeightGravel density: tons vs cubic yardsWhy equal volumes can weigh differently and how to use supplier density.
OrderingHow much extra gravel should you order?Think through waste, settlement, compaction and uncertain measurements.
Gravel calculator FAQ
How accurate is this gravel calculator?
The geometry is calculated directly from the dimensions you enter. Weight is an estimate because bulk density varies between materials, suppliers, moisture levels and gradations. For ordering, replace the preset density with supplier data when possible.
How do I calculate gravel for a driveway?
Measure the driveway length and width, enter the planned layer depth, then select the closest material type. For driveways, the correct base structure and compaction depend on soil, drainage and vehicle load, so use local contractor or engineering guidance for the required layers.
How many bags of gravel do I need?
Enter the bag size shown by your supplier. GravelScope divides the estimated project weight by the bag weight and rounds up to the next whole bag.
Why should I add a waste or compaction allowance?
An allowance helps account for uneven ground, spreading loss, settlement, compaction and measurement error. It is adjustable because the appropriate percentage depends on the job.
Is GravelScope free?
Yes. The calculator is free to use and does not require an account.