Decimal Unix Timestamp – Convert Fractional Seconds

Local only

Explain how decimal Unix seconds map to millisecond precision.

Multi-row timestamp converter

Compare timestamps and ISO 8601 dates. Inputs without an offset use UTC.

Row 1Timestamp -> Date
11/14/2023, 10:13:20 PM
ISO: 2023-11-14T22:13:20.500ZSeconds: 1700000000Milliseconds: 1700000000500

Fractional Unix time

How are decimal Unix timestamp seconds converted?

A decimal Unix timestamp can encode sub-second precision. VetaTool multiplies second-based values by 1000 before creating the date, so .5 seconds becomes 500 milliseconds. This tool is free to use. No account or payment is required.

Last updated

What you can do here

  • Unix seconds and milliseconds conversion
  • ISO 8601 parsing
  • Explicit timezone interpretation
  • Fractional and negative Unix timestamps
  • Browser-local processing

Steps

  1. Paste the decimal timestamp into Timestamp to Date.
  2. Inspect the ISO millisecond component.
  3. Use the Milliseconds detail when the receiving system needs integer millisecond precision.

The Seconds detail is an integer floor

The ISO and Milliseconds details preserve the Date's millisecond precision. The displayed Seconds detail is floored to an integer Unix-seconds value.

Half-second Unix timestamp

The .5 fraction becomes 500 milliseconds.

Timestamp

1700000000.5

UTC details

ISO: 2023-11-14T22:13:20.500Z
Seconds: 1700000000
Milliseconds: 1700000000500

Common questions

Frequently asked questions

Does VetaTool discard the decimal fraction?

No. The ISO and millisecond details preserve millisecond precision.

Why is Seconds shown without .5?

That detail is intentionally the floored integer Unix-seconds representation.

Recommended next steps

13-Digit Unix TimestampInterpret common 13-digit Unix values as milliseconds instead of seconds.10-Digit Unix TimestampInterpret common 10-digit Unix values as seconds and confirm the ISO date.Unix Timestamp Converter OnlineConvert Unix seconds, milliseconds, ISO 8601 dates, and timezone-aware values locally.

Debugging a specific Timestamp issue? Browse Timestamp troubleshooting.