NTP Timestamp Converter
Paste an NTP timestamp (seconds since January 1, 1900) and instantly see the UTC date, ISO 8601 string, and Unix equivalent. Useful when reading packet captures, NTP server logs, or network diagnostics.
About NTP timestamps
Network Time Protocol uses January 1, 1900 as its epoch — 70 years earlier than Unix time. The full NTP format is a 64-bit fixed-point number: the upper 32 bits hold whole seconds, the lower 32 bits hold fractions of a second. This gives a resolution of about 232 picoseconds and a range of 136 years per era.
In practice you most often see NTP seconds (the integer part) in packet captures and server logs. The current era 0 value for 2026 is around 3,960,000,000 — a 10-digit number close to the 32-bit maximum (4,294,967,295). Era 0 will wrap on February 7, 2036.
Epoch offsets at a glance
| Format | Epoch | Offset from Unix |
|---|---|---|
| NTP | 1900-01-01 | +2,208,988,800 s |
| Unix | 1970-01-01 | — |
| Cocoa / Apple | 2001-01-01 | −978,307,200 s |
| .NET Ticks | 0001-01-01 | +62,135,596,800 s (×10,000,000 for ticks) |
| Windows FILETIME | 1601-01-01 | +11,644,473,600 s (×10,000,000 for 100-ns) |
Frequently asked questions
What is an NTP timestamp?
NTP (Network Time Protocol) timestamps count seconds since January 1, 1900 at 00:00:00 UTC. The full 64-bit NTP timestamp format uses 32 bits for whole seconds and 32 bits for fractions of a second, giving sub-nanosecond resolution. This converter handles the seconds part as a plain integer.
What is the difference between NTP time and Unix time?
Unix time counts from January 1, 1970; NTP time counts from January 1, 1900. The offset is exactly 2,208,988,800 seconds (70 years, accounting for 17 leap years between 1900 and 1970). To convert: NTP = Unix + 2208988800; Unix = NTP - 2208988800.
What is an NTP era and when does era 0 wrap?
The 32-bit NTP seconds field wraps around at 2^32 - 1 = 4,294,967,295, which corresponds to February 7, 2036. After that date, NTP enters era 1 — the 32-bit counter resets to zero and starts over. Era 0 runs from 1900-01-01 to 2036-02-07; era 1 starts at 2036-02-07. This converter accepts integer values beyond 4,294,967,295, which are treated as era 1+ values without wrapping.
How do I read an NTP timestamp from a packet capture?
In Wireshark, NTP timestamps appear in the NTP layer under 'Reference Timestamp', 'Originate Timestamp', etc. Wireshark decodes these to human-readable dates automatically. If you need the raw integer, look at the hex dump: the 4-byte integer starting at the field offset. Convert from big-endian hex to decimal, then use this converter.
Does NTP account for leap seconds?
No — standard NTP timestamps do not encode leap seconds. When a leap second is inserted, an NTP server may repeat the same second twice. This means NTP-derived Unix time may be off by accumulated leap seconds vs TAI (International Atomic Time).