Date & Time Tools

Dates cause a steady share of software bugs: a timestamp in seconds treated as milliseconds, a date parsed in the wrong time zone, or a format string that works in one library and not another. These tools show you what a value means before you build on it.

The Unix timestamp converter shows the current epoch time and translates any timestamp to a readable date in UTC and your local zone. It detects seconds versus milliseconds for you. For example, 1767225600 and 1767225600000 both resolve to 1 January 2026, 00:00 UTC. The date converter accepts most date strings and reformats them into ISO 8601, RFC 2822, locale formats or a custom pattern you define, with time-zone conversion built in.

The time zone converter lines up one moment across several zones, and the date difference calculator counts the years, months, days and business days between two dates. All of these tools run in your browser, so they are safe for any data and quick enough to use in the middle of a debugging session.

Which tool for which job

  • Read a timestamp like 1767225600 from a log or a database

    Unix Timestamp Converter. Seconds and milliseconds are detected for you, and the date is shown in UTC and in your local zone.

  • Reformat a date for an API that expects ISO 8601 or RFC 2822

    Date Format Converter. Paste the date in whatever form you have it, then pick an output format or write your own pattern.

  • Find a meeting time that works across offices

    Time Zone Converter. One moment is lined up in several zones at once, using the daylight saving rules for that date.

  • Count the working days until a deadline

    Date Difference Calculator. Business days skip Saturdays and Sundays. Public holidays differ by country and are not subtracted, so take those off yourself.

Other tool categories

Specifications and references

This tool follows the specifications below. Read them when you need the exact normative wording, for example to settle an edge case between two implementations.

Frequently Asked Questions

Is a Unix timestamp in seconds or milliseconds?

It depends on what produced it. Unix tools, PHP's time(), Python's time.time() and most databases count seconds. JavaScript's Date.now() and Java's System.currentTimeMillis() count milliseconds. For current dates, a 10-digit number is seconds and a 13-digit number is milliseconds.

Should I store dates in UTC?

Store moments that already happened, such as created_at, in UTC and convert them to local time only for display. A future event tied to a place, such as a 09:00 meeting in Jakarta, is safer stored as the local time plus an IANA zone name like Asia/Jakarta, because a country can change its offset or its daylight saving rules before the date arrives.

What does the Z at the end of a timestamp mean?

Z marks the time as UTC, the same as an offset of +00:00. 2026-10-26T05:00:00Z and 2026-10-26T12:00:00+07:00 are the same instant. A timestamp with neither Z nor an offset is ambiguous, and parsers disagree on how to read it, so include the offset whenever you write one.

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