Timestamp Alchemist — Convert Any Time Format
Auto-detects 11 timestamp formats (epoch s/ms/μs/ns, ISO 8601, RFC 2822, Windows FILETIME, .NET Ticks, MongoDB ObjectId, Microsoft JSON Date, Excel serial) and renders 14 outputs side by side.
What it is
A timestamp tool that doesn’t ask you what format your input is. It looks at the magnitude and shape, infers the format, and renders every other format side by side — plus calendar derivatives (day of week, day of year, ISO week, quarter, relative-to-now).
What it detects
- Epoch seconds (Unix,
time.time()) — the bedrock - Epoch milliseconds (JS
Date.now(), JavacurrentTimeMillis) - Epoch microseconds (Python
time_ns() / 1000) - Epoch nanoseconds (Go
time.Now().UnixNano()) - ISO 8601 / RFC 3339 (
2026-05-12T18:00:00Z) - RFC 2822 (HTTP
Date:headers, email —Sat, 11 May 2024 13:46:40 GMT) - Windows FILETIME (100ns since 1601-01-01 —
133741968000000000) - .NET DateTime.Ticks (100ns since 0001-01-01 —
638669520000000000) - Microsoft JSON Date (
/Date(1731400000000)/) - MongoDB ObjectId (24-hex; first 8 chars are unix seconds)
- Excel / Google Sheets serial (days since 1900-01-01 with the 1900 leap-year bug accounted for)
Detection is magnitude-based — a 17-digit number is FILETIME, an 18-digit one is .NET Ticks, a 13-digit one is epoch ms, and so on. The rules cover every dev-tool timestamp you’ll see in the wild.
Why it matters
There’s a meaningful gap between knowing “epoch milliseconds” and being able to do the conversion in your head when staring at 133741968000000000 in a security log. This tool closes the loop — paste once, see everything, copy the format you need.
How it ships
Single HTML file, ~18KB. Zero dependencies. The detection table, BigInt math for Windows/.NET Ticks (JS numbers lose precision past 2^53), and ISO-week computation are 280 lines of vanilla JavaScript. Works air-gapped.