Unix Timestamp Converter

Quick Answer

Last updated: 3 November 2026 ·How we calculate this: seconds since the Unix epoch, 1 January 1970 UTC

How This Unix Timestamp Converter Works

Choose timestamp to date, and enter a Unix timestamp in seconds or milliseconds. The converter shows the date and time in UTC, in your own time zone and in ISO 8601 format, plus the weekday and how long ago or how far ahead it is. Choose date to timestamp to go the other way: enter a date and time, pick UTC or your local zone, and get the timestamp in seconds and milliseconds.

How to Use the Unix Timestamp Converter

1. Choose timestamp to date or date to timestamp.
2. Enter the timestamp, or the date and time.
3. For a date, choose UTC or your local time zone.
4. Press Calculate.
5. Read the timestamp, UTC and local times and ISO 8601 format.

Core Formulas

• Timestamp: seconds since 1970-01-01 00:00:00 UTC
• Milliseconds: seconds × 1,000
• Days since the epoch: timestamp ÷ 86,400
• One day: 86,400 seconds. One week: 604,800 seconds
• Local time: UTC + your time zone offset

Key Terms

• Unix time: the number of seconds since 1 January 1970 00:00:00 UTC.
• Epoch: the starting point of a time system, here 1 January 1970 UTC.
• UTC: Coordinated Universal Time, the world’s reference time.
• ISO 8601: an international standard for writing dates and times.
• Year 2038 problem: the overflow of 32-bit signed Unix time on 19 January 2038.

Worked Example

Convert 1,700,000,000 to a date.

• 1,700,000,000 ÷ 86,400 = 19,675 whole days, with 80,000 seconds left over
• 80,000 seconds = 22 hours, 13 minutes and 20 seconds
• 19,675 days after 1 January 1970 is 14 November 2023, so the time is 22:13:20 UTC

Real-Life Examples

• Reading logs: turn timestamps in server logs into readable times.
• APIs and databases: check values stored as epoch seconds or milliseconds.
• Scheduling: find the timestamp for a future date to set an expiry.
• The 2038 problem: 32-bit signed time ends at 2,147,483,647, which is 2038-01-19 03:14:07 UTC.

Unix Time vs ISO 8601

• Unix time: one number, easy for computers to store and compare.
• ISO 8601: readable text like 2024-01-01T00:00:00Z, with Z meaning UTC.
• Both: describe the same moment, so you can convert either way.

Notable Unix Timestamps

Tips

• Check the digits: 10 digits is usually seconds, 13 digits milliseconds.
• Store in UTC: convert to local time only when showing it to people.
• Negative timestamps: are dates before 1970.
• Daylight saving time: local times shift, but the timestamp does not.

Getting Unix Time in Code

Most programming languages have a built-in way to read the current Unix time or convert a timestamp to a date.

• JavaScript: Math.floor(Date.now() / 1000) gives seconds, and new Date(ts * 1000) turns seconds back into a date.
• Python: int(time.time()) gives seconds, and datetime.fromtimestamp(ts, timezone.utc) gives a UTC date.
• PHP: time() gives seconds, and date('Y-m-d H:i:s', ts) formats it.
• Linux shell: date +%s prints the current timestamp.

Remember that JavaScript works in milliseconds, while most other languages and databases work in seconds. Mixing the two is the most common cause of dates that land in 1970 or far in the future.

Common Mistakes to Avoid

• Mixing seconds and milliseconds. A 13-digit number read as seconds is thousands of years ahead.
• Forgetting the time zone. The same timestamp shows different local times around the world.
• Storing local time. Use UTC in databases to avoid daylight saving problems.
• Assuming leap seconds count. Unix time skips them.
• Using 32-bit time. It overflows in January 2038.

Frequently Asked Questions

References & Sources