Is my timestamp in seconds or milliseconds?

Count the digits: 10 digits is seconds (good until the year 2286), 13 digits is milliseconds. Pasting seconds where milliseconds are expected lands you centuries in the future — the wrong scale is usually obvious as soon as you convert.

Why does the converted time shift by hours?

Timezone interpretation. ISO strings like 2026-10-05T08:00:00Z name an exact moment (Z = UTC), but "2026-10-05 08:00" without a zone is ambiguous and gets read as your local time. A +8h shift almost always means one side treated a zone-less string as UTC and the other as local.

Which timestamp format should I store in my database?

Either UTC ISO 8601 strings or integer Unix timestamps — both are unambiguous. What you must avoid is zone-less datetime strings in local time: they break the moment a server, a user or daylight saving changes the timezone.

Date Converter — Guide

Convert between date formats online — ISO 8601, RFC 3339, UTC, locale, Excel, Mongo ObjectID and Unix timestamps.

What it is and when to use it

A single moment in time wears many coats, and this tool converts between all of them: Unix timestamps (seconds or milliseconds), ISO 8601, RFC 3339 and RFC 7231 strings, UTC, your locale-formatted string, the Excel serial number (days since 1900-01-01), and the leading 4-byte timestamp embedded in a Mongo ObjectID. Where a format names no timezone, your browser local zone is applied — so "now" on this page may read a different wall-clock than a UTC log line for the same instant. Everyday uses: turning a timestamp from a log or database field into a readable local time, checking whether an expiry (a JWT exp, a cache TTL, a Mongo-created document) is already in the past, and generating values for test fixtures.

Converts a date between many formats — Unix timestamps, ISO 8601, RFC 3339, RFC 7231, UTC, locale strings, Excel serial numbers and Mongo ObjectIDs.

How to use it

Use the current time or enter one manually
Read the Unix timestamp and the formatted results
Note whether you need seconds or milliseconds

A worked example

Paste a sample date

2026-10-05T08:00:00Z

Copy this into the tool, or open Date Converter

Things that trip people up

Unix timestamps are usually seconds (10 digits), while JavaScript Date.now() is milliseconds (13 digits)

Questions people ask

Is my timestamp in seconds or milliseconds?: Count the digits: 10 digits is seconds (good until the year 2286), 13 digits is milliseconds. Pasting seconds where milliseconds are expected lands you centuries in the future — the wrong scale is usually obvious as soon as you convert.
Why does the converted time shift by hours?: Timezone interpretation. ISO strings like 2026-10-05T08:00:00Z name an exact moment (Z = UTC), but "2026-10-05 08:00" without a zone is ambiguous and gets read as your local time. A +8h shift almost always means one side treated a zone-less string as UTC and the other as local.
Which timestamp format should I store in my database?: Either UTC ISO 8601 strings or integer Unix timestamps — both are unambiguous. What you must avoid is zone-less datetime strings in local time: they break the moment a server, a user or daylight saving changes the timezone.

Next steps

Open the Date Converter tool

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