Unix Timestamp to Date Time Conversion Tool
A Unix timestamp (also known as Unix time or POSIX time) is a system for describing points in time. It is defined as the number of seconds (or milliseconds) that have elapsed since the Unix epoch (00:00:00 UTC on 1 January 1970). This time representation is widely used in computer systems.
Timestamps represent UTC time, unaffected by time zones, making them ideal for cross-timezone applications
Numeric format facilitates time calculations and comparisons
More efficient storage compared to date-time strings
Handling date and time in programming, performing time calculations and comparisons
Storing time information in databases for efficient indexing and querying
Passing time parameters in web APIs, avoiding timezone issues
There are two main timestamp formats:
In JavaScript, the Date object uses millisecond-level timestamps, while many other programming languages (such as PHP, Python) use second-level timestamps by default. This distinction is important to note when working with timestamps.
Q: How do timestamps relate to time zones?
A: Timestamps themselves are time zone independent - they represent UTC time. When converting a timestamp to local time, you need to account for the local time zone. For example, timestamp 0 corresponds to January 1, 1970, 00:00:00 UTC, which is January 1, 1970, 08:00:00 in Beijing time (UTC+8).
Q: Why do timestamp conversions sometimes give incorrect results?
A: The most common reason is confusion between second-level and millisecond-level timestamps. A 10-digit timestamp is in seconds, while a 13-digit timestamp is in milliseconds. If you use a millisecond timestamp as a second timestamp, the conversion will be off by many years.
Q: Will timestamps overflow?
A: For 32-bit systems, on January 19, 2038 at 03:14:07 UTC, the second-level timestamp will reach 2^31-1 (2147483647), which may cause the Year 2038 problem, similar to the Y2K problem. However, most modern systems use 64-bit timestamps, which can represent a much wider range of time.
Q: How to use timestamps in programming?
A: Most programming languages provide functions for handling timestamps. For example, in JavaScript you can use Date.now() to get the current timestamp, new Date(timestamp) to convert a timestamp to a date object; in Python you can use time.time() to get the current timestamp, datetime.fromtimestamp(timestamp) to convert a timestamp to a datetime object.
The following tips may be helpful when working with timestamps: