Windows FILETIME Converter
Windows FILETIME counts 100-nanosecond intervals since January 1, 1601 UTC — the native timestamp of NTFS, registry and Win32 APIs. Related scales: OLE Automation dates (days since 1899-12-30, used by COM/Excel VBA) and LDAP (Windows NT time, same epoch as FILETIME, in 100ns).
This converter renders your date-time as the FILETIME tick count, the OLE Automation date, and the LDAP/AD timestamp so you can decode or generate each Windows-era representation.
Windows FILETIME Converter Quick Reference
| Format | Pattern / Description | Example 1 | Example 2 |
|---|---|---|---|
| Windows FILETIME | 100ns since 1601 | 134311050000000000 | 134116992000000000 |
| OLE Automation | Days since 1899 | 46247.6041666667 | 46023.0000000000 |
| LDAP / Win32 FileTime | 100ns since 1601-01-01 | 134311050000000000 | 134116992000000000 |
* Examples are rendered in UTC for the fixed sample instants above.
When to Use Windows FILETIME
Active Directory debugging
AD attributes like `whenCreated` and `lastLogon` store LDAP timestamps. Convert them to readable dates for audits and scripts.
Registry & NTFS forensics
Forensic tools report FILETIME values; convert them to clock time when correlating file activity with logs.
COM & VBA interop
OLE Automation dates surface in COM objects and Excel VBA `CDbl(Date)`. Verify serial values when bridging to other systems.
Frequently Asked Questions
What is Windows FILETIME?
A 64-bit count of 100-nanosecond intervals since 1601-01-01 UTC. Typical values are ~1.3×10¹⁷. It is stored in the low/high `FILETIME` structure halves.
Why does Windows use 1601 as the epoch?
The Gregorian calendar began in 1582; 1601 was chosen because it aligns with the Gregorian 400-year cycle, keeping date calculations simple for the original NT design.
What is the difference between FILETIME and LDAP timestamps?
None in scale — LDAP uses the same 100ns-since-1601 count. The terms are interchangeable; "LDAP timestamp" is the name used in Active Directory attributes.
What is an OLE Automation date?
A floating-point count of days since 1899-12-30, with the fractional part as time of day. 45251.5 = 2023-11-24 12:00. It underpins COM automation and Excel VBA.
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