Timestamp Cheat Sheet
Seconds and milliseconds timestamps plus the matching date for common reference points; updates instantly when you change the time zone.
Time zone
| Description | s | ms | Date |
|---|
タイムスタンプ チートシート
When writing code you often need fixed timestamps: the current second, midnight today, the 2038 limit 2147483647... This sheet lists common reference points once, with their seconds, milliseconds and readable date, updating instantly when you switch time zone.
Values are computed locally in your browser and need no network.
Features
- Common anchors — Covers now, start of today / this week / this month / this year, +1h, +7d, +1y, the 2038 limit and the epoch start.
- Two units — Each anchor shows both the seconds and the milliseconds timestamp.
- Time zone switch — Anchors like "midnight today" are interpreted in the time zone you pick.
How to use
- Pick a time zone in the dropdown.
- The table shows each anchor's seconds, milliseconds and date instantly.
FAQ
Which time zone is "midnight today" computed in?
The time zone you select. "Local time" means your browser's zone; "UTC" means midnight UTC.
What is the 2038 limit?
The largest seconds timestamp a signed 32-bit integer can hold is 2147483647, which is 2038-01-19 03:14:07 UTC. Systems past that overflow — this is the year-2038 problem.