Everyday Utility Calculators

The odds and ends — the calculations that come up a few times a year and are just annoying enough to look up. What a trip costs in fuel. How long a 2,000-word article takes to read aloud. Whether a wider tire will make the speedometer lie.

None of these is complicated. All of them are easier to get right with the arithmetic laid out than with a half-remembered rule of thumb, and each one here shows the formula alongside the answer.