Landscaping · updated 2026
River Rock Calculator — How Many Tons
River rock is priced by the ton and spread by the inch — and at roughly 100 lbs per cubic foot, the conversion is straightforward. This river rock calculator takes your bed's dimensions and depth and returns tons plus 2026 delivered costs. Three inches is the standard depth for weed suppression and a finished look; two inches works for a thin top-dress over existing beds. Bulk delivery beats bags the moment you pass about a ton.
3 in standard for weed suppression; 2 in for top-dressing
Show the math
Volume = 20 × 10 × (3 ÷ 12) = 50 cu ft
Tons = 50 × 100 lbs/cu ft ÷ 2000 = 2.50 tons
Cost = 2.50 × $60–$120/ton (delivered)
What the numbers mean
Volume is the footprint multiplied by the material depth. Cubic yards help compare supplier quotes; tons are the purchase unit for asphalt and gravel.
The asphalt calculator applies 145 lb per cubic foot. The gravel calculator applies 110 lb per cubic foot. Asphalt also adds the waste factor you select.
The material cost is a national planning range before delivery, labor, excavation, base preparation, tax, or other project-specific charges.
2026 material prices
| Material | 2026 average price | Note |
|---|---|---|
| River rock, per ton | $60.00 – $120.00 / ton | Bulk delivered; size and color shift price |
| River rock, 0.5-cu-ft bag | $5.00 – $8.00 / 0.5-cu-ft bag | Retail; ~40 bags per ton |
| Landscape fabric, per sq ft | $0.15 – $0.30 / sq ft | Always lay it under rock |
Material prices: Wave 1 Batch 2 2026 national-average guide, Sep 2026. Local prices vary. 2026 U.S. national averages. Prices vary by region and retailer — confirm locally before buying.
Pro tips
- Always lay landscape fabric under river rock — without it, the stones sink into the soil within two seasons.
- Install steel or heavy plastic edging first; rock migrates onto lawns and walkways without a hard boundary.
- One ton covers about 80 sq ft at 3 in — use that to sanity-check any quote before you sign.
- Smaller rock (⅜–¾ in) covers smoother and stays put; 2-in-plus cobble is for dry creek beds and accents.
- Rinse-once rock is worth asking about — dusty quarry rock looks dull until the first few rains wash it.
- A 20×10 bed at 3 in needs 2.5 tons — about $150–$300 delivered, or ~100 half-cu-ft bags if you enjoy suffering.
Common questions
Frequently asked questions
How much river rock for a 20×10 bed at 3 inches?
200 sq ft × 0.25 ft = 50 cu ft × 100 lbs = 5,000 lbs = 2.5 tons.
What about 2 inches deep?
33.3 cu ft = 1.7 tons — fine for top-dressing, thin for weed control.
How much area does a ton cover?
About 80 sq ft at 3 in deep (2,000 ÷ 100 = 20 cu ft ÷ 0.25 ft).
Do I need landscape fabric under river rock?
Yes — it stops the rock sinking into soil and blocks most weeds.
River rock vs pea gravel?
River rock is larger, smoother, and more decorative at $60–$120/ton; pea gravel is smaller and cheaper at roughly $30–$75/ton.
Bagged or bulk river rock?
Bulk wins past about a ton — a 2.5-ton job is ~100 half-cu-ft bags at $5–$8 each versus $150–$300 delivered bulk.
Related calculators
Planning estimates only. Prices are 2026 U.S. national averages and vary by region — confirm with your local supplier before buying.