Unix Time in Milliseconds
A practical guide to millisecond timestamps in client and API workflows.
What is this tool?
This page helps you reason about Unix timestamps in milliseconds, which are common in JavaScript, telemetry, and browser events.
How to use it
Detect 13-digit values as milliseconds, convert to UTC/ISO for readability, and normalize to seconds when backend endpoints require 10-digit input.
Examples
- 1716547200000 ms -> 1716547200 s
- 1716547200 s -> 1716547200000 ms
Common use cases
- Frontend click and session analytics.
- Performance timing and Web Vitals.
- API event ingestion and trace stitching.
FAQ
- Why do frontend tools use milliseconds?
- Browser APIs such as Date.now return milliseconds for better temporal precision.
- How do I convert ms to seconds?
- Divide by 1000 and round or floor based on your API contract.