Landscape Rock Calculator

Measure the area, pick the rock size you are actually buying, and multiply area by depth to get a volume, then by that size's density to get a weight. This calculator does all three steps for you: pick a shape (rectangle, circle, ring, triangle, trapezoid, or a straight area entry), pick a size class, and the depth pre-fills to what that size needs. The key difference from a generic calculator is the density: it changes by size class above, so a ton of fine decorative rock and a ton of large cobble cover different amounts of ground at the same depth.

Depends on the area, the depth, and the size of rock, in that order of importance. Area and depth give you a volume; the size you pick then sets the density that converts that volume to a weight, and that density genuinely varies by size (see the reference table above), so a generic "one density fits all rock" calculator will be off by a meaningful margin once you move past pea-gravel-scale material. Enter your measurements above and pick the actual size you are buying for an accurate figure.

It depends heavily on the rock size, which is exactly what generic calculators miss. Fine, pea-gravel-scale rock (3/8"-3/4") covers roughly 60-90 sq ft per ton at a 2-3" depth; screened decorative rock (3/4"-1 1/2") covers a similar range at the same depth; but 1 1/2"-3" cobble needs a deeper 3-4" bed and covers somewhat less per ton once that extra depth is accounted for, and 3"-6" large cobble covers less still at its recommended 4-6" depth, since the void space between bigger pieces is doing more of the work. Use the calculator above with your own area for an exact figure by size.

Depends on the job. Fine chips (3/8"-3/4") suit small edged beds and areas near a house where loose material tracking matters. Screened decorative rock (3/4"-1 1/2") is the most common all-purpose size for beds and borders. Cobble (1 1/2"-3") and large cobble (3"-6") work better for dry creek beds, slopes and accent areas where a heavier, chunkier look is wanted and drifting matters less. Boulders (6"+) are placed individually as focal points, not spread as a bed at all, so this calculator has a separate mode for those.

It scales with the rock size, which is why this calculator's depth field pre-fills differently for each size class rather than defaulting to one number. Fine and small decorative rock (up to about 1 1/2") typically wants 2-3 inches. Cobble (1 1/2"-3") wants 3-4 inches. Large cobble (3"-6") wants 4-6 inches. Go shallower than a size's recommended minimum and pieces tend to sit loose on the surface and shift, rather than settling into a stable bed, and the calculator warns if your entered depth is below that size's minimum.

Roughly 1.0 to 1.6 tons per cubic yard for bedding rock, depending on size. The finer classes on this page run closer to 1.15-1.6 tons per yard, while 3"-6" large cobble runs lower, around 1.0-1.45 tons per yard, because the void space between larger pieces takes up more of that cubic yard. There is no single figure that is right for all landscape rock sizes, which is the core reason this calculator asks for a size before converting anything.

Roughly 0.6 to 0.9 cubic yards per ton for bedding rock, the reciprocal of the tons-per-yard figures above, and it varies the same way by size: finer rock (higher density) needs slightly less volume per ton than large cobble (lower density) does. Use the calculator above with your specific size selected rather than a single conversion factor.

This calculator will not give you a price, deliberately, since cost swings by rock type, region, supplier and order size in a way there is no reliable sourced figure for, the way there is for density. What it does give you is the tonnage to price against: get a per-ton quote from a local supplier for the size you have selected above, and multiply by the tonnage this calculator shows.

The same calculation as landscape rock: area times depth times density. If you are asking because you are comparing decorative stone sizes, use the size picker above; if you specifically mean structural, compacted stone for a driveway or base rather than a decorative bed, use the Gravel Calculator instead, since that tool models compaction, which decorative landscape rock never goes through.

Switch to Boulder mode above, enter the average diameter, and read the estimate. It models the boulder as a sphere of solid rock (granite/limestone average about 168.6 lb per cubic foot solid) rather than the loose bedding density used for a rock bed, since one boulder has no air gaps the way a pile of many smaller stones does. As a quick reference, a 24-inch diameter boulder weighs roughly 630-730 lb, and a 36-inch one weighs roughly a ton to 1.2 tons, since weight scales with the cube of diameter and climbs fast. The quick-reference table in Boulder mode covers several common diameters directly.

That is a design decision, not a math one. This calculator will not tell you how many boulders look right in a bed, since that depends on the layout you want. What it will do is tell you how much each one weighs and what a given count will cost and weigh in total, once you have decided on a diameter and a count, so you can budget delivery and placement accurately.

Only a small one. This calculator's boulder mode exists partly to answer this safely: most single boulders over a couple hundred pounds are beyond what one or two people should lift by hand, and a boulder that size arrives and gets placed with equipment, not by hand. Check the estimated weight above before planning to move one yourself.

Landscape rock is the broad category this calculator covers, spanning angular crushed stone and naturally rounded stone across a wide size range. River rock specifically means naturally rounded, water-tumbled stone, a narrower material identity within that range. If you know you are buying river rock specifically, the River Rock Calculator is sized for that material; use this calculator when you are working from a size (3/8" chips, cobble, boulders) rather than a specific rock identity.

Decomposed granite is the finest end of the decorative-aggregate spectrum, well under the 3/8" starting point of this calculator's size range, and it is often used as a stabilized path or patio surface rather than a rock bed. If you are working with material fine enough to compact into a walkable surface, the Decomposed Granite Calculator is the right tool; this one starts where DG leaves off.

Most landscape-supply guidance recommends it for weed suppression, particularly under the finer size classes where soil can work its way up between small pieces over time. This calculator does not size fabric; the Landscape Fabric Calculator covers that separately, since it is priced and ordered by area, not by the rock's volume or weight.

No, deliberately not. Landscape rock is decorative: it is raked level and never rolled or compacted the way a gravel driveway base is, so there is no loose-to-compacted volume gap to account for here. The volume you measure is the volume you order. If you are building a structural base course instead of a decorative bed, use the Gravel Calculator, which does model compaction.

Yes. Every measurement field, including boulder diameter, accepts metric or imperial units and converts automatically, and results show weight in kilograms alongside tons and pounds. The densities behind the numbers are the same sourced figures either way, and only the displayed units change.

This calculator lets you enter your own price per bag or per cubic yard in the results panel, rather than assuming a national average that varies enormously by region and supplier. Enter the tonnage or yardage this calculator gives you, then check current pricing with a local supplier.

Pick the closest listed size class. The four bedding classes above span the full practical range from fine chips to large cobble, and density does not change sharply at any single inch mark, so the closest class will be accurate enough for ordering purposes. For anything 6 inches and larger, use Boulder mode instead, since that material is bought and placed as individual pieces, not spread as a bed.