Unix Timestamp Converter

Convert Between Unix Timestamps and Human-Readable Dates Instantly

Unix timestamps appear everywhere in software development—API responses, database records, log files, authentication tokens, file system metadata, and configuration files all regularly use them. They're the computer's native time format: a single integer representing the number of seconds that have elapsed since January 1, 1970, 00:00:00 UTC. Compact, unambiguous, and timezone-agnostic, they're ideal for machines. For humans, they're completely opaque. A timestamp like `1734567890` tells you nothing useful about what date and time it represents until it's converted.

Our free Unix timestamp converter handles both directions instantly. Enter a Unix timestamp to see the corresponding human-readable date and time in multiple formats and timezones. Enter a date to get the corresponding Unix timestamp. No mental arithmetic, no timezone calculation errors, and no need to write a quick script just to decode a timestamp from a log file or API response.

What Unix Timestamps Are and How They Work

A Unix timestamp (also called Unix time, POSIX time, or Epoch time) is an integer that counts the number of seconds since the Unix epoch: January 1, 1970, 00:00:00 UTC. The word "since" is important—the epoch is the reference point, not a minimum value. Negative timestamps represent dates before 1970; the timestamp for January 1, 1960 would be a negative number.

The design is elegant in its simplicity: no timezone complexity, no calendar ambiguity, no leap year arithmetic. Because UTC has no daylight saving time adjustments, a Unix timestamp always refers to a single, unambiguous instant in time regardless of where in the world it's evaluated. Converting to local time requires knowing the offset between UTC and the local timezone, which is what timezone conversion adds on top of the raw timestamp.

The current Unix timestamp is always increasing. At the moment this was written, the timestamp was approximately 1,740,000,000—about 55 years' worth of seconds. Each second that passes, every Unix timestamp increments by 1 on every computer in the world, simultaneously, regardless of local clock settings or timezone.

Why Developers Encounter Unix Timestamps Constantly

API Responses and JWT Tokens

REST APIs frequently return dates and times as Unix timestamps rather than formatted date strings because they're more compact, unambiguous, and easier for client applications to parse than regional date format strings. JWT (JSON Web Token) authentication tokens use Unix timestamps in their `iat` (issued at), `exp` (expiration), and `nbf` (not before) claims. When debugging authentication issues, decoding a JWT and reading the timestamp values to see whether a token is expired or not yet valid is a routine step that requires quick timestamp-to-date conversion.

Database Records

Many databases store dates as integer Unix timestamps, particularly older MySQL tables (using INTEGER columns instead of DATETIME), Redis keys with expiration times, and MongoDB documents with numeric timestamp fields. Interpreting these values when inspecting database records directly requires conversion to understand what date the number represents.

Log File Analysis

Web server logs, application logs, and system logs frequently use Unix timestamps for their timing fields because they parse and sort efficiently. When reviewing log entries to reconstruct the timeline of an incident or debug a time-related issue, converting the log timestamps to human-readable times helps you correlate events with what was happening at specific moments.

Cache and Session Expiration

Redis keys, browser cookies, HTTP cache headers, and many application-level caching systems express expiration times as Unix timestamps. The `Expires` and `Set-Cookie` headers can include Unix timestamps; Redis TTL calculations often work in seconds from the current timestamp. Understanding whether a particular cache entry has expired—and when it will expire—requires comparing timestamps in a form you can actually read.

Millisecond Timestamps

Modern JavaScript applications, many APIs, and some database systems use timestamps in milliseconds rather than seconds—multiplying the standard Unix timestamp by 1,000. A millisecond timestamp looks like `1734567890000` rather than `1734567890`. If a timestamp seems larger than expected or doesn't convert to a sensible date at second granularity, it's almost certainly a millisecond timestamp. Divide by 1,000 to convert it to a standard Unix timestamp before conversion, or enter it directly and let the converter detect the format automatically based on the number of digits.

Timezone Handling in Timestamp Conversion

Unix timestamps represent UTC moments. Converting to local time requires adding or subtracting the timezone offset. New York (UTC-5 in winter, UTC-4 in summer with daylight saving) is five hours behind UTC; Tokyo (UTC+9) is nine hours ahead. A timestamp that corresponds to noon UTC would be 7 AM in New York and 9 PM in Tokyo—the same moment in time, expressed in different local times.

The timezone offset adjustment is what makes "what time is this timestamp in my timezone?" a non-trivial question when daylight saving time is involved. UTC is a fixed reference that never adjusts for seasonal time changes, but local times in DST-observing regions shift by one hour twice per year. Our converter handles this correctly by referencing the appropriate offset for the specified timezone at the specific date in question.

Free, Private, and Instant

The Unix timestamp converter runs entirely in your browser. No timestamps or dates you enter are transmitted to any server or stored anywhere. The tool is completely free with no account required. Convert timestamps from any context—API responses, database fields, log files, JWT tokens—with immediate, accurate results.