River Rock Calculator

Measure the area (or, for a dry creek bed, the channel length and its average width), pick the river rock size you are actually buying, and the calculator multiplies area by depth to get a volume, then by that size's density to get a weight. Depth pre-fills to the recommended depth for your chosen size, since bigger rock needs a deeper bed to sit stable and cover what's underneath, and it stays editable. The result is a tonnage range to order against, with the higher number being the safer one to ask your supplier for.

It depends on the size, mainly through the depth that size needs rather than through a different density. Fine, 3/8 to 3/4 inch river rock at its 2 inch recommended depth covers noticeably more ground per ton than 3 to 8 inch jumbo rock does at its 5 to 6 inch recommended depth, even though the loose bulk density used for both is roughly the same, about 1.3 to 1.7 tons per cubic yard. Use the calculator above with your own area and chosen size for an exact figure rather than a single rule-of-thumb number.

Depends on the job. 3/8 to 3/4 inch pea-scale pebbles suit small, edged decorative beds. 3/4 to 1 1/2 inch is the standard, most commonly sold retail size for general beds and borders. 1 to 3 inch "creek rock" is the size most often used for a dry creek bed's main channel, heavy enough to stay put and small enough to lay by hand. 3 to 5 inch and 3 to 8 inch classes work as accent rock, creek-bed edging, and the bottom of a channel section that actually carries water, where a coarser size resists being washed downstream.

It scales with the rock size, which is why this calculator's depth field pre-fills differently for each size class. Fine and standard sizes (up to about 1 1/2 inch) typically want 2 to 3 inches. Creek rock (1 to 3 inch) wants about 3 inches. Large river rock (3 to 5 inch) wants about 4 inches, and jumbo or cobble mix (3 to 8 inch) wants 5 to 6 inches. Go shallower than a size's recommended minimum and individual pieces tend to sit loose on top of the fabric instead of settling into a finished-looking bed.

Roughly 2,600 to 3,400 lb per cubic yard (about 1.3 to 1.7 short tons), loose and never compacted. That range brackets two real sources rather than asserting one precise figure: LA County Public Works' government loose-rock schedule (2,570 lb/yd3) on the low end, and a density back-calculated from a working landscape supply yard's published coverage figures on the high end, since naturally rounded, washed river stone tends to pack somewhat tighter than a generic loose-rock catch-all.

This calculator will not give you a price, deliberately, since cost swings by size, region, supplier and order size in a way there is no reliable sourced figure for, the way there is for weight and coverage. What it gives you is the tonnage to price against: get a per-ton quote for the specific size you have selected above, and multiply by the tonnage this calculator shows, using the top of the range so one delivery covers the job.

For the most common retail size (3/4 to 1 1/2 inch) at its recommended 2 to 3 inch depth, a ton covers somewhere in the neighborhood of 90 to 100 square feet, based on published landscape-supply coverage figures. That is roughly a 9 by 10 foot bed, or a generous decorative border along one side of an average patio. Larger sizes cover noticeably less at their own, deeper recommended depth. Use the calculator above with your actual area for a specific figure.

Switch to "A dry creek bed" mode above rather than trying to force the channel into a rectangle. Enter the channel's length and its average width, using the width at a typical, representative point rather than the widest spot, since a real creek bed tapers along its length. Pick a size (1 to 3 inch creek rock is the size most commonly specified for a main channel) and set the depth, and the calculator runs the same area times depth times density math as any other shape, just against a footprint measured the way a creek bed is actually shaped.

Use the dry creek bed mode above with your channel's length and average width. A typical residential dry creek bed, for example 30 feet long by 3 feet average wide at a 3 inch depth of 1 to 3 inch creek rock, comes out to roughly 1.1 to 1.4 tons. That is only an example: length, width, size and depth all move the answer, so enter your own measurements rather than treating this figure as a fixed rate.

It is the standard material for a visible, surface-level dry creek bed or swale that channels runoff away from a downspout or a low, wet spot in the yard, and its rounded shape drains freely since there are no fines to clog the gaps between pieces. For that kind of surface drainage, lean toward the coarser end of the size range so the stone resists being washed downstream in a storm. For water that needs to be carried away below grade through a buried, perforated pipe rather than across the surface, see the French Drain Calculator instead; that is a different structure with a different material spec, not a bigger version of a dry creek bed.

River rock is naturally rounded, water-tumbled stone, a specific material identity. Landscape rock is the broader category this site's Landscape Rock Calculator covers, spanning both rounded river stone and angular crushed stone across a wide size range, plus a dedicated mode for individually placed boulders. If you know you are buying river rock specifically, or you are building a dry creek bed, this calculator is sized for that; use the Landscape Rock Calculator when you are working from a size or you need the boulder-by-the-piece mode.

Gravel, as this site's Gravel Calculator models it, is angular, crushed aggregate built to be compacted into a structural base, for driveways, parking areas and patio bases, and its calculator accounts for the volume lost to compaction. River rock is smooth and rounded, sold and placed loose, raked level and never compacted, for decorative beds, borders and dry creek beds. Do not substitute one for the other structurally: rounded river rock will not lock together and bind the way angular gravel does, so it is the wrong material under a driveway.

Most landscape-supply guidance recommends it, both for weed suppression and to keep the rock from working its way down into the soil over time, which is also why bigger sizes need a deeper bed: enough depth to fully hide the fabric underneath. This calculator does not size the fabric itself, since that is priced and ordered by area rather than by the rock's volume or weight.

Calculate above and read it straight off the results: the panel converts your total into a bag count using a standard half-cubic-foot bag, alongside the equivalent pickup-truck and dump-truck loads. Because river rock is heavy for its volume, that bag count grows large fast, so check the bulk delivery note next to it before committing to bags for anything past a small bed.

Bulk, past about three cubic yards, the same crossover this site's other aggregate calculators use. Below that, bagged river rock is workable for a small bed or border. Above it, bulk delivery is almost always cheaper and far less physical effort than carrying bags, particularly since river rock runs heavier per cubic foot than mulch or soil.

In small amounts. A half-ton pickup can carry roughly half a cubic yard of loose river rock, about a third of a level bed, and at 1.3 to 1.7 tons per cubic yard that adds up to more than the axle, springs and brakes are rated for well before the bed looks full. Load the front third of the bed and make more trips, or take a bulk delivery once the job passes a couple of cubic yards.

Yes. Every measurement field, including the dry creek bed's length and width, accepts metric or imperial units and converts automatically, and results show weight in kilograms and metric tonnes alongside tons, and volume in cubic metres and litres alongside cubic yards. The densities behind the numbers are the same sourced figures either way, only the displayed units change.

Pick the closest listed size class. The five classes above span the practical range sold as loose bedding stone, from pea-scale pebbles through jumbo cobble mix, and density does not change sharply at any single inch mark, so the closest class will be accurate enough for ordering. For true boulders (roughly 8 inch and larger, placed individually rather than spread as a bed), use the Landscape Rock Calculator's boulder mode instead.