Gravel Calculator for Drainage
French drains and trenches use clean, coarse gravel. Enter the trench length, width, and depth for cubic yards and tons.
Shape
Units
Area: 0.0 sq ft
Planning more than one thing? Open the Yard Planner → to trace your whole yard over an aerial photo and total every material at once.
How to measure for gravel
- Measure the length and width of your area in feet.
- Multiply them for square feet (or just enter length and width above).
- Choose a depth — we default to 2 inches for gravel.
- Read your total in cubic yards, or the number of bags.
Gravel for Drainage coverage at a glance (2" deep)
| Area (sq ft) | Cubic yards | Bags |
|---|---|---|
| 100 | 0.7 | 37 |
| 200 | 1.4 | 74 |
| 300 | 2.0 | 111 |
| 500 | 3.4 | 184 |
| 1,000 | 6.8 | 367 |
Includes a 10% overage allowance. Estimates are low-fi — confirm with your supplier.
Frequently asked questions
What size gravel is best for drainage?
Clean, angular gravel about 3/4 inch (sometimes called drainage or #57 stone) lets water move freely and resists clogging.
How do I calculate gravel for a French drain?
Treat the trench as a long rectangle: length × width × depth. Enter those above; we convert to cubic yards and tons.