Unit converters

Unit conversion is applied arithmetic: multiply by a defined factor, possibly add an offset (temperature), read the result. The tools here cover the eight physical quantities most people convert in daily life — length, weight, volume, temperature, speed, area, pressure, and energy — each as a single comprehensive converter that handles every pair of units in that quantity, with the conversion factor shown alongside the answer.

Every factor derives from a single documented reference. Length, weight, and their area and volume derivatives use the 1959 international yard-and-pound agreement (1 yard = exactly 0.9144 m, 1 pound = exactly 0.45359237 kg) — so every imperial ↔ metric conversion is exact to floating-point precision, not an approximation. Temperature uses the standard offsets between Celsius, Fahrenheit, Kelvin, and Rankine, flagging values below absolute zero when they occur. Pressure and energy route through their SI units (pascal, joule) to keep every pair mutually consistent.

These are general-purpose tools. For the niche cases — troy weight, Korean pyeong, historical British units, Mach-at-altitude, gauge-vs-absolute pressure distinctions — each converter page documents what it does and doesn't cover. Incumbent conversion sites win the mega-volume exact-match queries ("km to miles", "kg to lbs") through years of backlinks; these tools exist so someone already on Toolsnug has the whole kit on hand without bouncing out to another site.