ClockZone is a free online toolkit for everyday time tasks. It has countdowns, timers, a stopwatch, world clocks, alarms, holiday calendars, time-difference and DST tools, a date calculator, a timezone converter, an interval timer, a multi-timer and a chess clock.
The site states that all tools are completely free. There is no registration and nothing to download or install, and it runs in the browser.
ClockZone was built to put everyday time tools such as timers, world clocks and date calculators in one place that works in the browser without registration.