Time & Date Tools

Time is the format developers get wrong most often, and the reason is that a timestamp means different things to different systems. A Unix timestamp counts seconds (or milliseconds) since 1970-01-01 00:00:00 UTC. An ISO 8601 string carries a date, a time and a timezone offset in one readable value. A cron expression describes a repeating schedule. The three are different answers to the question when, and this category covers all of them.

The timestamp tools convert between the raw number and a human date in either direction. The converter reads a Unix timestamp - seconds or milliseconds, it detects which - and shows the local time, the UTC time and the ISO string. The generator does the reverse, turning a date and time into the corresponding number. If you have ever printed a timestamp that read as 1970, these are the tools that catch the unit mistake.

The 1970 and 2038 problems deserve a mention because they are the classic bugs. A value of 0 or a tiny number means the epoch was read wrong or the seconds were multiplied wrong. The signed 32-bit limit of 2038-01-19 explains why older systems start failing around then. Both symptoms are visible instantly when a converter shows you the actual date behind a number.

Cron tools cover scheduling. The generator builds a cron expression from plain-language choices - every day at nine, weekdays at midnight - so you never hand-type five fields and wonder which order they go in. The parser does the reverse and explains any expression field by field, which is the fast way to audit an existing schedule before it fires a job at the wrong time.

Timezone is the thread running through all of it. A Unix timestamp is absolute: the same number is the same instant everywhere. An ISO string is absolute when it carries an offset. A cron expression is local to the machine that runs it. The tools keep these distinctions visible rather than hiding them, because most time bugs come from assuming a local time is a UTC time or vice versa.

All conversions happen locally in the browser, so you can paste real values from your logs or your database without concern. Choose the tool by the format you hold: a number, a date, or a schedule.