Calculators / Mulch, gravel and soil
River rock calculator: how much do you need?
Measure the bed or border and how deep you want it. You'll get the tons to order in bulk, or the bags for a small spot.
Updated · How we check our numbers
Order this much
1 ton
That's 0.6 cubic yards of river rock, or about 33 bags at 0.5 cu ft if you haul it yourself.
- Area
- 90 sq ft
- Depth
- 2 in
- Cubic yards
- 0.6 yd
- Tons
- 1
Estimate for planning only, not professional advice. Check the manufacturer’s instructions, your local code and a licensed professional before you buy, build or install. Use at your own risk. Terms.
area = 30 ft × 3 ft = 90 sq ft
volume = 90 sq ft × 2 in ÷ 12 = 15 cu ft = 0.6 cu yd
with 10% for compaction = 0.6 × 1.1 = 0.6 cu yd
tons = 0.6 × 1.3 t/yd = 0.8, rounded up to 1
We used 1.3 tons a yard for river rock. Stone runs 1.3 to 1.6 depending on size and how wet it is. Ask the yard what theirs weighs.
Put woven geotextile fabric down first. It keeps the stone from sinking into the mud and cuts down on weeds.
See woven geotextile fabric on Amazon (opens Amazon in a new tab)As an Amazon Associate we earn from qualifying purchases.
How we work it out
We work out the cubic yards, add 10% for settling, then use 1.3 tons a yard for river rock. That's the low end for stone, since round rock packs loose.
cubic yards = sq ft × depth in inches ÷ 12 ÷ 27
tons = cubic yards × 1.1 × 1.3
Small jobs get a bag count too. Most bagged rock at the store is 0.5 cu ft. Bigger stones leave bigger gaps, so go deep enough to hide the fabric under it.
River rock rolls. It's fine in beds and along borders, but keep it off anywhere you drive.
Where the numbers come from
Not sure of the size?
More rock
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