About

A calculator on every solid.

ShapesIn3D draws a shape you can turn, then works out the volume and the surface area from the measurements you type.

Each page is one solid. The drawing uses the proportions of the numbers on that page, and the results name the formula they come from. A cube needs one edge. A cone needs a radius and a height. The ring needs the tube to sit clear of itself.

The drawing runs in your browser. Typing a measurement does not send that number to another site. There is no reader account. The shapes already on the homepage stay there.

If a visit counter is switched on, every public page loads the same snippet, either Google Analytics or Matomo, from a single file. Nothing is counted until that is switched on. The admin pages are marked so search engines do not index them.