How to Convert Unix Timestamps Online
Convert Unix timestamps to human-readable dates and back with our free Timestamp Converter. Supports milliseconds, seconds, and multiple timezones.
Steps
Enter a Unix timestamp
Type or paste a Unix timestamp into the input field. The tool automatically detects whether your timestamp is in seconds (10 digits, e.g., 1700000000) or milliseconds (13 digits, e.g., 1700000000000). You can also click 'Current Time' to populate the field with the current Unix timestamp.
Convert to human-readable date
Click Convert to see the timestamp expressed as a human-readable date and time. The output shows the date in UTC and in your local browser timezone by default, plus ISO 8601 format and RFC 2822 format.
View in multiple timezones
Use the timezone selector to see the same moment expressed in different timezones — useful when debugging logs from servers in different regions or scheduling events across timezones.
Convert a date to Unix timestamp
Switch to the reverse direction: enter a date and time in the date picker and click Convert to get the corresponding Unix timestamp in both seconds and milliseconds. This is useful for constructing date range filters in API queries.
Unix Timestamps in Programming
Unix timestamps are used pervasively in programming because they simplify date arithmetic. To check if something expired, just compare two timestamps: if (now > expiresAt) — no calendar math needed. To find events in a 30-day window, add 30 * 24 * 3600 seconds. To sort events chronologically, sort by timestamp number. Every major programming language has built-in Unix timestamp support: JavaScript has Date.now() (milliseconds), Date.getTime(), Math.floor(new Date()/1000) (seconds). Python has time.time() (float seconds), datetime.timestamp(). Unix/Linux shell: date +%s. SQL: UNIX_TIMESTAMP() in MySQL, EXTRACT(EPOCH FROM NOW()) in PostgreSQL. When you see a 10-digit number in a database, log file, or API response, there is a strong chance it is a Unix timestamp.
ISO 8601: The Human-Readable Alternative
While Unix timestamps are ideal for computation, ISO 8601 format (2024-01-15T09:30:00Z) is the standard for human-readable timestamps in APIs, logs, and data exchange. The 'Z' suffix means UTC. Timezone offsets are expressed as +HH:MM: 2024-01-15T17:30:00+08:00 is 9:30 AM UTC in Singapore time. ISO 8601 is unambiguous and sorts chronologically as a string — a significant advantage over many locale-specific formats like 01/15/24 (US) or 15/01/24 (UK) which are ambiguous and do not sort correctly. Modern REST APIs should always use ISO 8601 for timestamp fields rather than Unix timestamps, unless the client explicitly needs a numeric format for calculation purposes.
Frequently Asked Questions
A Unix timestamp (also called Unix time, POSIX time, or epoch time) is the number of seconds that have elapsed since 00:00:00 UTC on 1 January 1970, which is called the Unix epoch. It is the most universal way to represent a point in time in software because it is a single integer that does not depend on timezones, calendars, or locale settings. The current Unix timestamp is approximately 1.7 billion seconds (as of 2024).
Most Unix APIs use seconds-precision timestamps (10 digits). JavaScript's Date.now() and many modern APIs use milliseconds-precision (13 digits) for higher resolution timing. If you see a timestamp like 1700000000000, it is in milliseconds — divide by 1000 to get the seconds value. If you see 1700000000, it is in seconds. Our tool auto-detects based on digit count.
On 19 January 2038 at 03:14:07 UTC, 32-bit signed Unix timestamps will overflow from the maximum positive value back to a large negative number, causing software that stores timestamps as 32-bit integers to misinterpret dates. Modern systems use 64-bit integers for timestamps, which will not overflow for approximately 292 billion years. Most actively maintained software has been updated; legacy embedded systems and old databases are the primary concern.