How this instrument works
Ordering crushed stone starts as a volume problem — how much space a bed, base, or path fills — but ends as a weight problem, since suppliers price and deliver stone by the ton. The bridge between the two is density: multiply volume by the stone's weight per unit volume, and cubic feet or cubic yards converts directly into tons.
That density figure genuinely varies rather than being one fixed number. Crushed stone commonly runs somewhere around 95 to 105 pounds per cubic foot, but the exact figure depends on the stone type, its gradation (how much fine material fills the gaps between larger pieces), and how compacted or wet it is when weighed. This calculator defaults to 100 lb/ft³ as a reasonable planning midpoint, but it's an editable input specifically because your supplier's actual product may sit meaningfully above or below that — check a delivery ticket or ask your quarry for their material's specific weight if the order is large enough that the difference matters.
The volume math itself is exact geometry: length times width times depth, converted from cubic feet to cubic yards by dividing by 27 (since a cubic yard is 3×3×3 = 27 cubic feet). Depth is the dimension most often mis-entered — this calculator takes it in inches and converts to feet internally, so double-check you're entering the intended depth of stone, not the depth of an entire excavation that includes a base layer below it.
- Enter the length and width of the area to be covered, in feet.
- Enter the intended stone depth, in inches.
- Enter the stone's density in pounds per cubic foot — the default of 100 is a typical planning figure; adjust it if your supplier quotes a specific density.
- Read Volume in cubic yards and the resulting Weight in US tons.
Worked example — a 15 × 10 ft path, 3 inches deep
A garden path measures 15 feet by 10 feet, with a planned 3-inch depth of crushed stone at the default 100 lb/ft³ density. Volume = 15 × 10 × (3/12) = 37.5 cubic feet, which converts to 37.5 / 27 = 1.3889 cubic yards. Weight = 37.5 × 100 = 3,750 lb, or 3,750 / 2,000 = 1.875 tons to order.
Scale that same path up to a 20 × 20 ft patio base at a 4-inch depth, using a denser 105 lb/ft³ stone: volume = 400 × (4/12) = 133.333 cubic feet = 4.938 cubic yards; weight = 133.333 × 105 = 14,000 lb, exactly 7 tons — a reminder that both a larger footprint and a denser material push the final tonnage up.
Questions
How do I convert a stone bed's dimensions into tons?
Multiply length by width by depth (converted to feet) to get volume in cubic feet, then multiply by the stone's density to get weight in pounds, and divide by 2,000 to get US tons. This calculator does that chain automatically and also reports the intermediate cubic-yard figure, since some suppliers quote by volume instead of weight.
What density should I use for crushed stone?
Around 95 to 105 pounds per cubic foot is a commonly cited range, with 100 lb/ft³ used here as a reasonable planning midpoint. The exact figure depends on the specific stone type, its gradation, and moisture content, so treat the default as a starting point — if your supplier lists a specific density on a spec sheet or delivery ticket, use that number instead for a more accurate order.
Why does this calculator ask for depth in inches but length and width in feet?
Because that matches how these dimensions are typically specified in practice — plan footprints in feet, stone depths in inches. The calculator converts the depth to feet internally before computing volume, so you don't have to do that conversion by hand or risk an error entering a fractional foot depth.
How much does a ton of crushed stone cover?
It depends on both the depth you're spreading it and its density, but at a common 100 lb/ft³ density and 2-inch depth, one ton covers roughly 100 square feet; at 4 inches deep, that drops to roughly 50 square feet. Run your own depth and density through this calculator's reverse relationship (area = tons × 2,000 / density / (depth/12)) for an exact figure.
Should I order extra stone beyond the calculated amount?
Most suppliers and contractors add a small margin, commonly 5-10%, to cover an uneven subgrade, settling, or minor measurement error, since running short mid-job usually costs more in a second delivery than ordering a bit extra up front. This calculator reports the raw geometric figure; adding a margin on top is a judgment call based on your site's condition.