Length Converter

Convert weight between kilograms, pounds, ounces, grams, milligrams, metric tons, and stone. NIST-exact conversion factors.

Convert speed between mph, km/h, m/s, knots, and feet per second. Instant speed unit converter with all common units.

Convert between digital storage units — bits, bytes, KB/MB/GB/TB/PB (decimal) and KiB/MiB/GiB/TiB/PiB (binary). See why your 1TB drive shows as 931GB.

Convert knitting needle and crochet hook sizes between US, UK/Canadian, and metric (mm), plus a yarn-weight-to-size reference chart. Free, instant, no sign-up.

Enter your bag's dimensions and weight to instantly check if it fits carry-on limits for American, Delta, United, Ryanair, easyJet, and 12+ other airlines.

Get the exact passport and visa photo size in inches, mm, and pixels for the US, UK, Schengen, India, Canada, Australia, and China, plus head-height guidance.

Convert screw and bolt sizes between metric (M), UNC, UNF, and wood/sheet-metal screw gauge, with the nearest equivalent and tap drill size. Free, instant.