How time zones actually behave, and how to work across them. Written by the person who builds the tools on this site, mostly in response to getting it wrong first.
Why these guides exist
Every tool on this site started as a question somebody actually had: what time is the call, why did it move, why does my code get India wrong. The calculators answer the question. These pages explain the thing underneath it, so the answer makes sense rather than just appearing.
They are written by hand, one at a time, by Nishanth Narayanan. Nishanth Narayanan builds and maintains GlobalTimeTools from Coimbatore, India. He works with distributed teams across Indian, European and US time zones, which is where most of these questions came from.

