Surface Area Calculator

Spheres, cylinders, and cones each have a total outer surface that this tool measures in a single step. Engineers and builders rely on those figures for everyday decisions, from sizing the sheet metal a part will consume to estimating how much paint or coating a structure needs. As of 2026, with tighter attention to sustainable production and resource efficiency, getting these numbers right matters even more for trimming waste in fields like aerospace and construction.

Behind each result is the standard geometric formula for the shape. A sphere's surface area (A) equals 4πr², where 'r' is the radius. A cylinder uses 2πrh + 2πr², which adds the two circular bases to the curved side wall, with 'r' as the radius and 'h' as the height. A cone follows πr(r + √(h² + r²)), combining its circular base with the slanted lateral surface, again with 'r' as the radius and 'h' as the height.

Accurate output depends on entering every measurement in the same unit, since mixing units throws off the final number. Watch the distinction between diameter and radius as well: the radius is half the diameter, and swapping the two is the usual source of error. Note also that the values here represent total surface area including the bases, so check whether your project actually calls for the lateral surface alone.