Three-dimensional geometry

Volume calculator

Choose a solid, enter dimensions in one unit, and calculate cubic volume with practical conversions to liters, US gallons, cubic meters, and cubic feet.

Formulas used for each solid

A rectangular prism uses length × width × height, and a cube uses side³. A cylinder uses πr²h, a cone uses πr²h ÷ 3, and a sphere uses 4πr³ ÷ 3. The triangular prism uses half of base × triangle height, multiplied by prism length. The square pyramid uses base side² × perpendicular height ÷ 3.

Use one length unit for every dimension

The selected unit applies to all entered dimensions. Mixing centimeters and inches, radius and diameter, or slanted and perpendicular height produces the wrong result even if each number is valid. Radius is half the full diameter. For cones and pyramids, height means the perpendicular distance from the base plane to the apex.

Cubic units and liquid capacity

Scaling length by ten scales volume by one thousand. One cubic meter equals 1,000 liters. US liquid gallons are converted from liters using 3.785411784 liters per gallon. The calculator reports geometric interior volume; usable liquid capacity can be smaller because of wall thickness, fittings, fill limits, displacement, shape irregularity, or manufacturing tolerances.

Measurements control accuracy

The calculator retains more digits than most physical measurements justify. Round the final answer to the precision of the least certain dimension, and add an appropriate allowance only when the real task calls for one. Use the volume converter when a known volume only needs unit conversion.

These ideal-shape calculations are educational estimates. Verify drawings, inside versus outside dimensions, units, tolerances, safety margins, material specifications, and applicable engineering requirements before ordering, filling, fabricating, or loading anything.