Time Tools
Unix timestamps, ISO 8601, timezone conversion, cron expressions, date arithmetic — every time-related utility a developer needs.
5 tools in this category
Cron Expression Parser
Explain cron schedules and preview the next 10 runs.
Date Difference Calculator
Calculate the difference between two dates in every unit.
ISO 8601 Parser
Parse and format ISO 8601 dates, durations, and intervals.
Timezone Converter
Convert between timezones with DST and multi-target support.
Unix Timestamp Converter
Convert between Unix epoch and human-readable dates
Dealing with time is famously hard. Between Unix epochs, ISO 8601, RFC 3339, timezone databases, daylight saving, and leap seconds, every project eventually needs a tool to sanity-check its output. This suite gives you each transformation in isolation so you can debug one concept at a time.
Unix timestamps and formats
A Unix timestamp is seconds since 1970-01-01 UTC. JavaScript uses milliseconds; SQL databases often use microseconds. Our Unix Timestamp tool auto-detects the magnitude and converts in both directions. ISO 8601 is the international standard (2026-04-20T15:30:00Z). RFC 3339 is the subset HTTP and JSON typically use. If a date is a string and not obviously one of the above, paste it here first.
Timezones done right
Timezones are not offsets. America/New_York is a timezone; -05:00 is an offset that changes twice a year. Always store timezones in IANA format (the tz database) and convert at display time. Our Timezone Converter uses the browser's built-in Intl API, which is backed by the same CLDR data every modern OS ships.
Cron, explained
Cron syntax has evolved into several dialects. Classic Unix cron is 5 fields. Quartz (used by Java schedulers and AWS EventBridge) uses 6 or 7 including seconds and years. Our Cron tool parses both, explains each field in English, and shows the next five fire times so you can verify intent before committing the schedule.
Frequently asked questions
Why does my timestamp show a different date here than in my logs?
Logs are usually in UTC; your browser shows the local timezone by default. The Unix Timestamp tool shows both. If you see a 5–8 hour discrepancy, that's the UTC-to-local offset.
Does the cron tool support AWS EventBridge schedules?
Yes — it handles the 6-field AWS syntax (minutes/hours/day-of-month/month/day-of-week/year). Quartz's `?` placeholder is accepted. Extended macros like `@every 5m` are Go-specific and are not supported.
How do you handle leap seconds?
JavaScript's `Date` object ignores leap seconds, so our tools do too. This matches virtually all application-level behavior. If you're doing sub-second astronomical work, use TAI time and a dedicated library.
What's the range of valid dates?
JavaScript Date supports ±100 million days from Unix epoch — approximately the year -271821 to +275760. Plenty for most use cases. The Unix Timestamp tool rejects anything outside this range with a clear error.