FILETIME / LDAP Timestamp Converter
Convert Windows FILETIME and LDAP/Active Directory 100-nanosecond timestamps to ISO 8601, Unix time, and readable dates — and back.
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What is FILETIME / LDAP Timestamp Converter?
The FILETIME / LDAP Timestamp Converter translates Windows FILETIME and Active Directory 100-nanosecond timestamps — 18-digit integers counted from January 1, 1601 UTC — into ISO 8601 dates, Unix timestamps, and readable local times, and converts dates back to FILETIME using exact BigInt arithmetic.
Key Benefits
- Exact BigInt conversion with zero precision loss
- Decodes lastLogon, pwdLastSet, accountExpires, and lockoutTime instantly
- Bidirectional: FILETIME to date and date to FILETIME
- Live FILETIME clock for the current moment
- Private and offline — nothing leaves the browser
Common Use Cases
- •Reading Active Directory user attributes exported from PowerShell or CSV
- •Decoding NTFS metadata and Windows event log timestamps
- •Debugging 1601-epoch values in LDAP tools such as ldapsearch or ADUC
- •Preparing accountExpires or similar values for provisioning scripts
- •Converting FILETIME to Unix time for cross-platform logging pipelines
How to Use the FILETIME / LDAP Timestamp Converter
- Paste the FILETIME value: Copy the 18-digit number from AD (lastLogon, pwdLastSet) or a Windows API result and paste it into the FILETIME field — digits only are kept.
- Read the instant results: The tool shows ISO 8601 UTC, Unix seconds and milliseconds, plus UTC and local readable dates, all computed with exact BigInt math.
- Convert a date back (optional): Pick any date and time in the Date field to get the exact FILETIME value for it — useful for scripting or setting future accountExpires values.
- Copy what you need: Every result row has a copy button; use the live clock card to grab the current FILETIME anytime.
Key Features
- Exact BigInt arithmetic — no precision loss on 18-digit values
- Live FILETIME clock of the current moment with one-click copy
- Instant output: ISO 8601, Unix seconds, milliseconds, UTC, and local time
- Bidirectional date picker to generate exact FILETIME values
- Range validation that flags Int64 sentinel values instead of wrong dates
- Fully offline and client-side — safe for internal AD data
Frequently Asked Questions
What is a FILETIME or LDAP timestamp?
It is a 64-bit integer counting 100-nanosecond intervals since January 1, 1601 00:00 UTC. Windows APIs and Active Directory attributes such as lastLogon, pwdLastSet, and accountExpires store dates this way, which is why they appear as huge 18-digit numbers.
Why does JavaScript convert my FILETIME to the wrong year?
18-digit values exceed Number.MAX_SAFE_INTEGER (2^53 − 1), so storing them in a regular JS Number silently loses the low digits. This tool uses BigInt for every step, keeping the value exact.
How do I convert FILETIME to Unix time manually?
Divide by 10,000,000 to get seconds since 1601, then subtract 11,644,473,600 (the seconds between 1601-01-01 and 1970-01-01). The tool shows both Unix seconds and milliseconds automatically.
What does 9223372036854775807 mean in Active Directory?
That is Int64.MaxValue — a sentinel meaning "never" (for example accountExpires never set or a lastLogon of an account that has never logged on). The converter flags it as out of range instead of rendering a far-future year.
Does my data leave the browser?
No. All parsing and conversion run locally in JavaScript — nothing is uploaded, making it safe for internal Active Directory exports.