Developer Toolbox

Unix timestamp converter

Convert between Unix seconds, milliseconds and zone-aware ISO times. Explicitly labels epoch 0, s/ms units, UTC (Z) and the chosen time zone so local wall-clock time is never mistaken for UTC.

Run in browser

Inputs and parameters

• input — Timestamp or zone-aware ISO time (empty = current real time)
• unit — Unit
• timeZone — Display time zone (IANA name, e.g. Asia/Shanghai)

Real example

unit=s, input=0; and unit=auto, input=1700000000000
→ 0 → seconds=0, milliseconds=0, isoUtc=1970-01-01T00:00:00.000Z (UTC, Z); 1700000000000 → interpretedUnit=ms, seconds=1700000000, isoUtc=2023-11-14T22:13:20.000Z

Limits and failure handling

Single-instant conversion only: no batch, duration, leap-second or calendar conversion; limited by the JavaScript Date range ±8.64e15 ms. Auto unit uses |n| ≥ 1e11 for ms — choose s/ms explicitly near the boundary. Input cap 256 bytes.

FAQ