NumberTally Volume Calculator
Find the volume of a box, a cylinder, a sphere, or a cone. Pick the shape, enter the dimensions, and get the volume instantly with the formula and the step-by-step working shown — plus the answer in liters, gallons, and cubic feet. Free, no sign-up.
Advanced options
The four volume formulas
Every volume is (base area) × (height) in disguise: box = l×w×h, cylinder = πr²h, sphere = ⁴⁄₃πr³, cone = ⅓πr²h. Notice the cone holds exactly one third of the cylinder with the same base and height — the diagram makes this visible.
Units: cubic, then liquid
Volume answers come in cubic units (cm³, in³). For containers, liquid units are more useful: 1 liter = 1,000 cm³, 1 US gallon ≈ 3,785 cm³, 1 cubic foot ≈ 28.3 liters. The converter below shows all of them at once.
Frequently Asked Questions
What is the formula for the volume of a sphere?
V = ⁴⁄₃πr³ — four-thirds pi times the radius cubed. A sphere with radius 3 has volume ⁴⁄₃π×27 = 36π ≈ 113.1.
Do I enter the radius or the diameter?
The formulas use the radius (half the diameter). For the sphere there's a checkbox if you measured the diameter — the calculator halves it for you.
What units is the volume measured in?
Cubic units matching your inputs: cm → cm³, inches → in³. Pick your input unit in Advanced options and the converter shows liters, gallons, and cubic feet too.
What is the volume of a cylinder?
V = πr²h — the area of the circular base times the height. A cylinder is just a circle extruded upward.
Why is a cone ⅓ of a cylinder?
Because the cone's cross-section shrinks linearly to a point. Calculus (or a classic dissection proof) shows the shrinking averages out to exactly one third of the full cylinder.