How to Calculate Gravel for a French drain
Follow these steps to get the right amount of gravel for any french drain project, then use the calculator below to skip the math.
- Measure the area. Multiply length × width in feet to get square footage.
- Apply standard depth. A french drain typically uses 12" of gravel.
- Convert to cubic yards. Area × (depth in inches ÷ 12) ÷ 27 = cubic yards.
- Add overage. Multiply by 1.10 to cover 10% waste.
- Round up. Always round up to the next whole ton or bag.
Calculate Gravel
You need
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ton
- Area
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- Volume
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- With 10% overage
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- Or in 0.5 cu ft bag
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- Estimated cost (US avg)
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