Unix Timestamp Converter

The Unix Timestamp Converter is an online tool for converting Unix timestamps into readable dates and times, and converting dates and times back into timestamps. Enter a timestamp or date, select the timestamp unit and target time zone, and view the conversion result instantly.

The tool also supports common date and time formats and ISO 8601 conversion. It is useful for software development, API debugging, database queries, server log analysis, and handling time across different time zones.

What Is a Unix Timestamp?

A Unix timestamp is a numeric representation of time measured from the Unix Epoch, which is defined as January 1, 1970, at 00:00:00 UTC.

Common timestamp units include:

• Seconds: Measures elapsed time in seconds. Current timestamps commonly contain around 10 digits.
• Milliseconds: Measures elapsed time in milliseconds. Current timestamps commonly contain around 13 digits.

Both units use the same time reference but differ in measurement precision. The number of digits changes depending on the date range, so digit length alone cannot reliably identify every timestamp unit.

Timestamp Converter Features

• Timestamp to date: Convert Unix timestamps in seconds or milliseconds into readable dates and times.
• Date to timestamp: Enter a date and time and calculate the corresponding Unix timestamp using a selected time zone.
• Automatic unit detection: Estimate whether an input is a seconds or milliseconds timestamp based on its numeric value.
• Manual unit selection: Explicitly select seconds or milliseconds when automatic detection may be ambiguous.
• Date format conversion: Support formats such as YYYY-MM-DD, HH:mm:ss, YYYY-MM-DD HH:mm:ss, and ISO 8601.
• Time zone conversion: Select common time zones in Asia, Europe, the Americas, and other regions to view local dates and times.

What Is the Difference Between Seconds and Milliseconds?

A seconds timestamp measures elapsed time in seconds, while a milliseconds timestamp measures it in milliseconds. Since 1,000 milliseconds equal one second, the millisecond timestamp for the same instant is usually 1,000 times the seconds timestamp.

Different programming languages and systems may use different timestamp units. For example, JavaScript's Date.now() returns a timestamp in milliseconds, while PHP's time() normally returns a timestamp in seconds. Always confirm the unit when handling API parameters, database fields, or application logs.

How Does Automatic Timestamp Detection Work?

Automatic detection estimates the timestamp unit from the absolute numeric value. This can quickly distinguish common 10-digit seconds values from 13-digit milliseconds values.

Automatic detection is an estimate based on the numeric range, not a definitive determination. When processing historical data, far-future dates, or values generated by specialized systems, select seconds or milliseconds manually to ensure the conversion is correct.

How to Convert a Unix Timestamp to a Date

Enter the timestamp, select automatic detection, seconds, or milliseconds as the input unit, and choose the target time zone. The tool interprets the timestamp as a specific point in time and displays its date, time, and ISO 8601 representation in the selected time zone.

The same Unix timestamp may appear as different dates and clock times in different time zones, but it always represents the same instant. For example, one timestamp can be displayed as UTC, Shanghai time, or New York local time.

How to Convert a Date to a Unix Timestamp

Select date-to-timestamp mode, enter a date or date and time, and specify the corresponding time zone. The tool uses the local date and time together with the selected time zone to calculate the Unix timestamp in both seconds and milliseconds.

When entering a date and time without time zone information, select the correct time zone. ISO 8601 strings containing Z or a UTC offset should be interpreted using the time zone information included in the string.

Supported Date and Time Formats

The format converter supports common representations, including:

• Date and time: YYYY-MM-DD HH:mm:ss, for example, 2026-11-01 14:30:00.
• Date: YYYY-MM-DD, for example, 2026-11-01.
• Time: HH:mm:ss, for example, 14:30:00.
• ISO 8601: For example, 2026-11-01T06:30:00Z or a date and time containing an explicit UTC offset.

Select the input and output formats to convert dates, times, or date-time values into the required representation. Date-only and time-only formats do not contain complete time zone information. When exchanging time data between systems, follow the time zone conventions defined by the application or API.

ISO 8601 vs. Unix Timestamps

A Unix timestamp represents a point in time as a number, while ISO 8601 uses a standardized date and time string. For example, 2026-11-01T06:30:00Z represents a UTC date and time. The trailing Z indicates a zero UTC offset.

An ISO 8601 string can also contain an explicit UTC offset, such as 2026-11-01T14:30:00+08:00. Unlike a date and time without time zone information, a string containing Z or an explicit offset identifies a specific instant.

Unix timestamps are commonly used in program calculations, database storage, and API data exchange. ISO 8601 is frequently used in logs, API responses, and date-time exchange between systems. Choose the format required by the target system or API specification.

Time Zone Considerations

A Unix timestamp represents a specific instant and does not belong to a particular city or local time zone. The time zone only affects how that instant is displayed as a date and clock time.

This tool uses IANA time zone identifiers such as Asia/Shanghai, Asia/Tokyo, Europe/London, and America/New_York. Some regions observe daylight saving time, so their UTC offsets can change depending on the date. For cross-region time calculations, use the appropriate regional time zone instead of relying on a fixed UTC offset.

Common Uses of a Timestamp Converter

• Software development: Check timestamps generated by PHP, Python, Java, JavaScript, and other programming languages.
• API debugging: Decode timestamp fields in API request parameters and response data.
• Database queries: Convert stored Unix timestamps into readable dates and times.
• Server log analysis: Convert numeric timestamps in logs into readable dates and times to help investigate issues.
• Frontend development: Work with JavaScript millisecond timestamps and Date objects.
• Cross-time-zone processing: Compare dates, times, and UTC offsets across different regions.

Things to Check When Converting Timestamps

• Confirm whether the input uses seconds or milliseconds. Using the wrong unit can produce a significantly incorrect result.
• When converting a date and time to a timestamp, confirm the time zone associated with the input.
• ISO 8601 strings containing Z or a UTC offset should be parsed using their own time zone information.
• Automatic detection is intended for common timestamps. Select the unit manually for specialized data.
• When calculating across time zones, consider daylight saving time and regional time zone rules.

Use this Unix Timestamp Converter to convert seconds and milliseconds to readable dates and times, convert dates back into timestamps, and check common date formats, ISO 8601 representations, and time zone differences.