Gravel Calculator for a French Drain
Estimate drainage stone for a French drain of any length.
Use this free gravel calculator to estimate how much gravel you need based on area and depth. It calculates volume in cubic yards and converts the result to tons, helping you plan gravel for driveways, paver patio bases, French drains, walkways, and shed bases.
Cubic yards
1.85
50 ft³
Tons
2.59
~1.4 tons per yd³
Area
200
square feet
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Handy picks for this project on Amazon.
Landscape Fabric
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Steel Garden Rake
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Heavy-Duty Wheelbarrow
Move bulk material fast
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Hand Tamper
Compact base layers before paving
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How does the gravel calculator work?
Gravel is estimated by volume, then converted to tons. Multiply the area by the depth (converted to feet) to get cubic feet, divide by 27 for cubic yards, and multiply by ~1.4 for tons.
Formula: tons = (L × W × D/12 ÷ 27) × 1.4
What else do people ask about this calculator?
What size gravel is best for a French drain?
¾ in to 1½ in washed round drainage stone is standard. It's free of fines that would clog the perforated pipe and it lets water move quickly through the trench.
How much gravel for a 50 ft French drain?
A 50 ft trench that's 6 in wide by 18 in deep uses about 1.4 cubic yards (roughly 2 tons) of drainage stone. Order 10% extra to backfill around the pipe evenly.
How much gravel do I need for a driveway?
A typical residential driveway uses 4–6 in of gravel. For a 20×10 ft driveway at 4 in, you need about 2.5 yd³ (3.5 tons).
How many tons of gravel in a cubic yard?
About 1.4 tons per cubic yard for average crushed stone. Denser stone (river rock) can be 1.5+ tons/yd³.
How deep should gravel be for drainage?
3–4 in for a top layer; 6+ in for a base beneath pavers or concrete.
Which related calculators should I use next?
Where can I learn more about these materials?
Weights, coverage, types and buying tips for the materials this calculator estimates.
Gravel guide
How much gravel you need, what a cubic yard weighs, and which type fits your project.
Asphalt guide
Weight
Crushed Stone guide
Crushed stone sizes suit different applications: #57 stone is commonly used for drainage, concrete, and paver bases; #8 stone works for fine paver bedding, chip seal, and decorative applications; and ¾″ minus, also called crusher run, compacts into a hard driveway base.
Pea Gravel guide
Pea gravel is smooth, rounded ⅜″ stone commonly used for patios, paths, play areas, dog runs, and drainage. One cubic yard weighs about 2,700–2,800 lb and covers approximately 100 sq ft at a 3″ depth. For walkable surfaces, use a 2–3″ layer and edging to keep the gravel contained.
Limestone guide
Crushed limestone for base, drainage, and agricultural use.
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