Unix Timestamp Converter
Timestamps to dates and back, in Vietnam time (UTC+07:00), seconds or milliseconds.
How it works
A Unix timestamp is the number of seconds since 00:00:00 UTC on 1 January 1970 — the epoch. It carries no time zone: one timestamp is one instant everywhere, and the zone only decides what a clock in that place reads at the time. That is why systems store time this way rather than as "14:30 on 5 March".
This page reads timestamps in Vietnam time, which is UTC+07:00 all year with no daylight saving. That makes the arithmetic simpler than the same tool anywhere that changes its clocks: no 23-hour days, no hour that happens twice, and no instant that maps to two different local times.
The commonest confusion is seconds against milliseconds. Java and JavaScript work in milliseconds; Unix, PHP, Python and most databases work in seconds. Paste a milliseconds value where seconds are expected and you land in the year 56000. This page guesses from the magnitude — a seconds timestamp for any realistic date has at most 10 digits, the same instant in milliseconds has 13 — and lets you override it.
The ISO 8601 output spells out `+07:00` rather than ending in `Z`. Both describe the same instant, but the offset form keeps the information about what the clock read locally, which `Z` has thrown away.
Formula
local parts = (timestamp in seconds × 1000 + 7 × 3600 × 1000), read with the UTC getters
Shift by the offset, then read through the UTC getters rather than the local ones. The local getters apply the host machine’s zone — which during a build is whatever the CI runner happens to be set to.
Worked example
Midnight on 1 January 2026 in Vietnam:
- Vietnam time
- 2026-01-01 00:00:00
- The same instant in UTC
- 2025-12-31 17:00:00
- Unix timestamp (seconds)
- 1767200400
- Unix timestamp (milliseconds)
- 1767200400000
- ISO 8601 with offset
- 2026-01-01T00:00:00+07:00
The single number 1767200400 is midnight in Hanoi and five in the afternoon the day before in London. A timestamp does not belong to a zone; the zone only decides how to read it.
Frequently asked questions
What is a Unix timestamp?
The number of seconds since 00:00:00 UTC on 1 January 1970. It is the most common way for a computer to store an instant, because it is just a number and depends on no time zone or date format.
Is my timestamp in seconds or milliseconds?
Count the digits. For dates around now, seconds have 10 and milliseconds have 13. This page guesses from the magnitude and lets you override the guess.
Why is the date seven hours off from another converter?
Most converters show UTC. This one shows Vietnam time (UTC+07:00), so the same timestamp reads seven hours later here. Both are correct; they differ in which zone they display.
Does Vietnam observe daylight saving?
No. It stays on UTC+07:00 year-round, which is why none of these conversions ever hits the repeated or skipped hour that trips up the same tool in countries that change their clocks.
What is the year 2038 problem?
Systems storing timestamps in a signed 32-bit integer overflow on 19 January 2038. It does not affect this page — JavaScript uses 64-bit floats — but it is worth knowing if you work with older systems.
Why does the field start at midnight rather than now?
Because this page is prerendered to a static file, and a value that changes every second would be stale the moment the file was written. The "use the current time" button fills in the instant you press it.