How much stone mulch do I need?
Same math as gravel: sq ft × depth in feet ÷ 27 = cubic yards. A 50 sq ft bed at 3" depth needs about 0.46 cubic yards — round up.
Stone Mulch Calculator
Decorative stone and river rock beds use 2–4 inches over landscape fabric. Enter bed dimensions — we convert to cubic yards the same way as gravel paths.
Garden beds
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Project settings
Use the project-specific starting depth, then verify locally
Default 10% for settling
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Default 0.5 cu ft for bagged gravel
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Uses the bag size above
Stone vs organic mulch
Stone does not decompose and rarely needs topping up. Wood mulch refreshes every 1–2 years but improves soil as it breaks down. See mulch vs bark vs compost for planting beds with living shrubs.
For driveways and paths, use the dedicated gravel calculator with deeper default depth.
Weight and delivery
Stone is heavier than mulch — confirm driveway or gate access for bulk dumps. A cubic yard of river rock can weigh 2,000+ lbs depending on stone type.
Related guides
Frequently asked questions
Stone mulch vs wood mulch?
Stone does not decompose and rarely needs topping up. Wood mulch breaks down and needs refresh every 1–2 years. Stone is heavier — confirm delivery access.
What depth for river rock beds?
2–3 inches is common for decorative rock over fabric. Use 4 inches only if you want a thicker visible layer — depth increases weight and cost quickly.
Related calculators
Mulch Calculators · https://mulch-calculators.com/stone-mulch-calculator/