By Zencalcy Editorial TeamLast reviewed About us
River rock is rounded, so it settles differently from crushed stone: it packs less tightly, drains well, and a bag goes further than its weight suggests. The calculator uses a 1,500 kg/m³ bulk density for loose rounded stone and reports the bag count as well.
Smooth river stone for beds, edging and dry creek beds.
V = L × W × D W = V × ρ Cost = V × price
Depth is entered in inches. Bulk density is taken as 1,500 kg/m³ (loose rounded river stone); real material varies with moisture and compaction, so treat the total as an estimate and add 5–10% for settling.
| Symbol | Meaning |
|---|---|
| L, W | Length and width of the area being covered. |
| D | Spread depth of the material. |
| V | Volume in cubic yards (and cubic metres). |
| ρ | Bulk density of the material. |
| W | Total weight, shown in pounds and US tons. |
100 sq ft at 4 inches is 33.3 cu ft, or 1.23 cu yd. That is about 1,850 kg (2.03 tons) of river rock.
Continue with the Gravel Calculator, Sand Calculator, Rock Calculator, or the Limestone Calculator — or browse more materials & quantities and all construction calculators.
About 162 sq ft at 2 inches and 81 sq ft at 4 inches.
Results use standard construction estimating arithmetic: volumes from measured area and depth, unit weights from published material densities, and code-referenced spans or clearances where the page names a code. Quantities are rounded up to whole saleable units and include the stated waste allowance. These tools are planning aids, not structural design, and do not replace a licensed engineer, a local code check, or a contractor's site measurement.
Reference material used to build and check this calculator:
Last reviewed: September 2026. See how we build and check every tool on the about page.
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Content updated: September 2026