Surface Area Calculator

This calculator finds total surface area, lateral surface area (the sides only, excluding the top and bottom faces), and volume for six solid shapes — cube, rectangular prism, sphere, cylinder, cone, and square pyramid — reusing the same three dimension fields for all of them, though which fields actually matter changes completely depending on which shape is selected. For the default cylinder shape, only the first two dimension fields do anything: Dimension 1 acts as the radius and Dimension 2 as the height, and Dimension 3 stays hidden, since the cylinder's surface area formula never references it — that third field only appears once you switch to the rectangular prism, the one shape among the six that genuinely needs three independent measurements. Of the two fields the cylinder does use, the radius carries noticeably more weight than the height: at the calculator's default measurements, nudging the radius by ten percent moves the total surface area by about twice the proportional amount that nudging the height by the same ten percent does, because the radius appears in both the circular end caps and the curved side, while the height only appears in the curved side.

For a sphere, lateral area and total surface area are reported as the exact same number, since a sphere has no flat base to separate out from its curved surface. Where this calculator falls short: it never checks that a shape's dimensions are physically sensible for that shape — a negative or absurdly disproportionate value is simply multiplied through the formula and displayed as though it were valid.