Unix Timestamp Unit Threshold – When Does VetaTool Use Milliseconds?

Local only

Document the converter's exact seconds-versus-milliseconds heuristic at its boundary.

Multi-row timestamp converter

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

Row 1Timestamp -> Date
3/3/1973, 9:46:40 AM
ISO: 1973-03-03T09:46:40.000ZSeconds: 100000000Milliseconds: 100000000000

Timestamp unit heuristic

At what value does VetaTool switch from seconds to milliseconds?

The converter treats absolute numeric values below 100,000,000,000 as seconds and values at or above that magnitude as milliseconds. The boundary value itself is therefore interpreted as 100000000000 milliseconds. This tool is free to use. No account or payment is required.

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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 100000000000 into Timestamp to Date mode.
  2. Confirm the details show 100000000000 milliseconds and 100000000 seconds.
  3. Use the producing API's documented unit whenever it is known.

The threshold is a VetaTool heuristic, not a Unix standard

Unix time itself does not define a universal digit-count detector. VetaTool uses this magnitude rule to make common interactive conversions convenient.

Threshold example

The exact boundary is interpreted as milliseconds.

Numeric timestamp

100000000000

UTC ISO

1973-03-03T09:46:40.000Z

Common questions

Frequently asked questions

What happens to 99999999999?

It is below the threshold and is interpreted as seconds by this converter.

Should my application copy this heuristic?

Prefer an explicit unit in your data contract. Heuristics are best used for interactive inspection.

Recommended next steps

11-Digit Unix TimestampSee why an 11-digit value can still represent Unix seconds rather than milliseconds.13-Digit Unix TimestampInterpret common 13-digit Unix values as milliseconds instead of seconds.Unix Timestamp Seconds vs MillisecondsCompare timestamp units and avoid common conversion mistakes.

Debugging a specific Timestamp issue? Browse Timestamp troubleshooting.