Unix Timestamp ↔ 日付

Unix time (epoch time) is the number of seconds elapsed since January 1, 1970, 00:00:00 UTC. It's the most common way to store time in databases, APIs, and logs, since it's just a single integer with no tie to a specific timezone or date format.

How to use it

• Timestamp → date: paste a number of seconds (or milliseconds) and the tool shows the date and time in your chosen timezone.
• Date → timestamp: pick a date and time to get the matching Unix timestamp.
• The "now" button fills in the current moment instantly — handy for testing an API or grabbing a fresh value.

Common uses

• Reading a created_at or expires_at field from an API response that arrived as a raw number.
• Checking whether a token or session has expired, given an expiry field in seconds since the epoch.
• Building a timestamp for test data or a date filter in a database query.

Things to keep in mind

Mixing up seconds and milliseconds is the most common mistake: JavaScript's Date.now() returns milliseconds, while most Unix APIs use seconds — a factor of 1000 off.

Unix time itself has no timezone — it's always UTC; a timezone is only applied when displaying the date to a person.