Converters

Learn how to convert between millimetres, centimetres, metres, kilometres, inches, feet, yards, and miles — with real examples for construction, furniture, running, and everyday use.

100,000 files of 200 bytes each can consume 400 MB. Cluster sizes, slack space and filesystem metadata explain the gap between file size and space on disk.

The hectare was deliberately designed as a human-scale agricultural unit (100m × 100m = 10,000 m²), sitting between the too-small square metre and too-large square kilometre for farm use. Here's why carbon sequestration and deforestation rates are expressed in hectares, why US bushel-per-acre and international tonne-per-hectare crop yield data require crop-specific conversion factors, and why urban density comparisons break down when cities use different area boundary definitions.

Pressure has so many units because medical, industrial, and meteorological fields all developed measurement systems independently before international standardization. Here's why blood pressure is still in mmHg globally (all clinical reference ranges are established in it), what industrial pressure ranges look like (gas cylinders at 200-300 bar vs arterial blood pressure at 0.157 atm), and why pressure unit errors in engineering specifications have caused real safety incidents.

Mach 1 at sea level is 1,225 km/h; Mach 1 at cruising altitude is only 1,062 km/h — because the speed of sound decreases with temperature, and temperature drops with altitude. Mach number is more useful than km/h for aviation because it directly measures proximity to compressibility effects. Here's the four speed regimes (subsonic, transonic, supersonic, hypersonic), why swept wings delay transonic effects, and why both aviation and maritime navigation use knots for the same geometric reason.

Learn how volume units like ml, litres, cups, fluid ounces, and gallons relate — including the US vs. UK difference — with real examples for cooking, fuel, medicine, and industry.

Learn how Celsius, Fahrenheit, and Kelvin relate to each other, key temperature reference points for weather and medicine, why Kelvin exists, and how to use a free temperature converter for cooking, travel, and science.

Learn how frequency units like Hz, kHz, MHz, GHz, and RPM relate to each other, with real examples from audio, radio, computing, and motor engineering — plus a free frequency converter.

Learn how time zones and UTC offsets work, why daylight saving time causes scheduling chaos, and how to use a free time zone converter for remote work, server logs, and international meetings.

Learn weight unit conversions including the troy ounce vs regular ounce difference, the UK stone unit, US vs UK vs metric tonnes, and how to convert body weight, luggage limits, and precious metals accurately.