GPS Time Converter
GPS time counts from January 6, 1980 00:00:00 UTC in units of GPS weeks and seconds of week. Unlike UTC it is a continuous atomic time scale — GPS time is currently ahead of UTC by 18 seconds because UTC inserts leap seconds while GPS does not.
This converter returns the GPS week number, seconds of week, the total GPS timestamp (ms), and the NMEA $GPRMC-style date/time string for any input date, covering the two representations used by receivers and navigation software.
GPS Time Converter Quick Reference
| Format | Pattern / Description | Example 1 | Example 2 |
|---|---|---|---|
| GPS Time | Epoch: 1980-01-06 | 1470666600 | 1451260800 |
| GPS Week & Seconds | Week Seconds | 2431 397800 | 2399 345600 |
| GPS NMEA ($GPRMC) | NMEA 0183 Sentence | $GPRMC,143000,A,... | $GPRMC,000000,A,... |
* Examples are rendered in UTC for the fixed sample instants above.
When to Use GPS Time
GNSS receiver development
RINEX logs, receiver firmware and NMEA parsers exchange GPS week/TOW. Convert UTC timestamps to GPS week & seconds for test vectors.
Navigation & surveying
Surveying software records GPS time; convert to civil time for reports, or generate the NMEA sentence your pipeline expects.
Time synchronization analysis
Compare GPS time against UTC to audit leap-second handling in NTP/PTP infrastructure.
Frequently Asked Questions
What is GPS time?
A continuous time scale counting weeks and seconds since 1980-01-06 00:00:00 UTC, with no leap seconds. It is maintained by the GPS atomic clock constellation.
Why is GPS time ahead of UTC?
UTC inserts leap seconds (currently 18) to track Earth's rotation; GPS time ignores them. GPS time = UTC + 18 s (as of 2026), constant until the next leap second.
What is GPS week?
The integer week number since the 1980 epoch. It is sent as 10 bits in the GPS message and rolls over every 1,024 weeks (~19.6 years) — the last rollover was April 2019.
What is seconds of week (TOW)?
The number of seconds since the start of the current GPS week (Sunday 00:00 GPS time), from 0 to 604,799. Together with the week number it fully identifies an instant.
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