Estimate river rock volume for a landscape bed or border.
This page estimates a decorative layer by volume. It does not establish that a particular rock is suitable for a drain, a compacted base or a walking surface. Ask for the named product and a sample before accepting a quote described only as “river rock.”
UC IPM identifies rock as an inorganic mulch and recommends fabric beneath rock mulch to reduce soil-and-stone mixing. Its guidance does not specify a drainage geotextile for your site. Read the rock-mulch context.
Choose the separator with the fabric decision guide, calculate the stone here, then use the bulk-versus-bags guide to reconcile the quote units. Keep edging, separator and delivery as distinct purchase lines.
Material-choice review: November 2, 2026. These are planning choices, not a site inspection or a drainage specification.
These are independent worksheets. Inputs do not transfer between them. Use the download button beside the result you want to keep.
Whole packages round up. Prices include only the items you enter. Delivery, tax and installation may be extra.
Two bag formats can supply the same bed volume with different bag counts. Compare exact product yields before comparing package prices.
Use a 12 × 12 ft bed and an illustrative 3 in loose coverage layer, with 10% extra. The coverage depth must suit the chosen rock and supplier guidance; this example does not choose stone size or a suitable depth.
Original hypothetical scenarios for checking the arithmetic. Depths, conversion factors and buying increments are editable assumptions, not construction or product recommendations. The two cases are alternatives, not quantities to add.
Factor 1; extra 10%; bag yield 0.5 cu ft; bulk increment none cu yd; individual bags.
Factor 1; extra 10%; bag yield 0.75 cu ft; bulk increment none cu yd; individual bags.
Loading a case replaces the multi-area worksheet’s measurements and resets its prices to unknown. Save your own worksheet first. These buttons require JavaScript; all example quantities remain readable above.
Both cases need the same 1.4667 cu yd before bag rounding, but buy 80 half-cubic-foot bags or 53 three-quarter-cubic-foot bags. The larger bag count is lower because its stated volume is larger, not because it spreads more thinly. Package-rounding surplus also differs. Equivalence of products must be confirmed before using price to choose.
Record rock size range, stated bag volume, price per bag and delivery terms. If bulk pricing is by weight, obtain the supplier’s product-specific US short tons per cubic yard; do not borrow a density from pea gravel.
Compare actual bag and bulk purchases only after the buying units match.
Combine non-overlapping rectangles at different depths, subtract exclusions and round bags once for the total. All rows must use the same material. This worksheet is independent of the quick calculator above.
How to split an irregular area · How to compare a bulk quote with bags
The rectangular volume approximates the space occupied by the stone layer, including voids. Large stones may need more depth to cover exposed soil.
Length (ft): 16 · Width (ft): 12 · Material depth (in): 3 · Bag yield (cu ft): 0.5 · Extra material (%): 10.
These inputs produce 1.96 cubic yards to order. Change the measurements above to match your project.
Measure landscape beds as a set of rectangles, excluding hardscape only where it displaces rock. Enter a depth compatible with the chosen stone size and the desired coverage, supplied by your landscape plan or supplier. The volume includes space between stones.
A 10 × 8 ft bed at 3 in occupies 0.7407 cu yd. Adding 10% gives 0.8148 cu yd. If a 4 sq ft feature occupies the entire layer, net area is 76 sq ft and adjusted volume falls to 0.7741 cu yd. A 0.5 cu ft bag yield would round that second result to 42 bags.
A layer thinner than the largest stones cannot be treated as a continuous, uniform slab. Increasing depth for visual coverage changes volume linearly, but individual large stones still create local gaps. Do not import a generic gravel density to price decorative stone by weight.
Confirm actual stone-size range, color mix, coverage guidance and the seller’s volume-to-weight basis. Order from a consistent batch if appearance matters. Account separately for bed edging and access restrictions on dumping bulk rock.
Size affects the depth needed for your intended coverage and the supplier’s bulk density. The formula uses those inputs rather than guessing them.
No. It estimates the occupied bulk layer, including voids, which is the relevant basis for a bulk-volume order.
This worksheet uses the geometry and editable assumptions shown above. Product specifications and local quotes determine the inputs.
YardTakeoff · Revised October 21, 2026 · Formula checks and scope · Report a calculation error