How we calculate

Last updated November 2, 2026.

Every calculator on this site runs in your browser. You type the lengths, the page converts them with the factors below, and the weight uses the density stored on that tool. The result is the shape you entered. It is not a test of the pile on the truck, so when the supplier ticket disagrees, type that density in.

Length factors

Lengths become meters before anything is multiplied. An inch is 0.0254, a foot is 0.3048, a yard is 0.9144, a meter is 1, a centimeter is 0.01, and a millimeter is 0.001. A cubic foot is 0.3048 cubed. A cubic yard is 0.9144 cubed, which works out to 0.764554857984 cubic meters. The gravel density chart uses those same two powers when it turns a density into tons per yard.

Volume and weight

A box is the three sides multiplied once they are in meters. A circle is pi times the radius squared, times the depth. A ring is the outer disk with the inner disk taken out. Kilograms are that cubic-meter volume times the kg/m3 figure on the page. Divide by 1,000 and you have tonnes. A short ton is 907.18474 kilograms, so short tons are the kilograms divided by 907.18474, and pounds are the short tons times 2,000.

What you see is rounded for display, to two digits after the decimal. The formula itself is not rounded a second time. On the retaining wall tool, the base line shows cubic meters and tonnes. The drainage line also shows cubic yards, cubic feet, and short tons, using the factors above.

Density defaults

Each material starts from one shared list, which is what the density chart displays. Clean gravel, pea gravel, sand, and the retaining-wall base all start at 1,600. Crushed stone, crusher run, quarry dust, limestone, and 411 start at 1,700. 304 starts at 1,920. Class 5, concrete, and asphalt start at 2,400. Fill and backfill start at 1,400. Topsoil starts at 1,300. Pool filter sand starts at 1,680. Aquarium gravel and decomposed granite start at 1,500. River rock starts at 1,525. Riprap starts at 1,550. Lava rock starts at 720. A checkbox lets you replace the starting number with the one on the ticket. The chart says which rows come from a published table and which are planning starts.

Counts that round up

The retaining wall calculator does not divide the wall area by the face area. The run is divided by the face width, and the height is divided by the face height. Each ratio is snapped with Math.round of the ratio times 1e9, then divided by 1e9, and then rounded up with Math.ceil. That snap keeps a value that is really a whole number from being nudged up by binary dust. Blocks are the two whole numbers multiplied. Buried blocks are the blocks in one course times the number of buried courses you type, and they stay off the main block line. Caps use the same round-up on the wall length divided by the cap length. A cap length of 0 means you are not ordering caps. Base gravel is length times trench width times trench depth. Drainage stone is length times thickness times height. Both use the density box, which starts at 1,600, and neither one hides a waste allowance inside the math.

Bag tools divide the volume by the yield stored for that bag, subtract a tiny 1e-9, and then round up. The subtraction keeps a count that is already a whole bag from ticking up because of floating-point noise. The yields themselves are on the concrete bag page.

Mix split

The cement, sand, and aggregate tool has three starting densities. Cement opens at 1,440 kg/m3. Sand opens at 1,600, the same start used for clean gravel. Coarse aggregate opens at 1,500 kg/m3. When the 1.54 switch is on, the wet volume is multiplied by 1.54 before the parts are shared out. Each material's volume is that dry volume times its part, divided by the sum of the parts, and the weight is the volume times the density in that box. How this split differs from IS 456 Table 9 is explained on concrete mix ratios.

What the result leaves out

You get the neat shape. Swell, compaction loss, spillage, and a soft subgrade are not added for you. Where a page has a cost line, it multiplies a price you type. It does not keep a market price. A block count or a yardage is a planning quantity, not a stamped design. Sourcing, and the address for a wrong figure, are on the editorial policy.