A short companion for Timestamp Converter: when it is useful, what it expects, and what to check before using the result.
What it does
Convert between Unix timestamps, ISO 8601 strings and local time, in both directions. It handles seconds and milliseconds, which is the mix-up that produces dates in 1970 or in the year 55000.
Use the tool
Open Timestamp Converter, add the input the tool asks for, run it, and check the output before using it elsewhere.
Input and output
- Input: text.
- Output: text.
- Category: Workflow.
Privacy and processing
Processing happens locally in your browser. This tool does not upload the input to ilham.dev.
Questions
Is my timestamp in seconds or milliseconds?
A ten-digit number is seconds; a thirteen-digit number is milliseconds. JavaScript's Date.now() returns milliseconds, while most Unix tooling works in seconds.
Why is my date off by a day?
Almost always a timezone issue. The converter shows UTC and your local zone side by side so you can see which one you were reading.
Related guide
For broader background, see Dates, Timestamps, and Time Zones.