Timestamp Converter
Convert Unix timestamps to readable dates and back, across any timezone.
When a timestamp converter is the right tool
Logs, APIs, and databases often store time as a Unix timestamp — seconds or milliseconds since 1 January 1970 UTC — which is hard to read. A converter is for that moment. You paste a number or an ISO date and get Unix seconds, Unix milliseconds, an ISO 8601 string, and a clock reading in a timezone you choose.
This page works in your browser. The timezone list is a fixed set of common zones, not every zone in the world. If you need to compare one instant across many cities at once, use the Time Zone Converter. If you need to add or subtract days, use the Date Calculator.
Use cases
Reading a Unix timestamp from a log or an API
Paste a 10-digit seconds value or a 13-digit milliseconds value. The table fills in the ISO string and the time in the zone you selected, so you can tell whether the event was this morning or last year. For example, 1705314600 is 10:30 UTC on 15 January 2024.
Turning an ISO date into Unix time
Paste a string such as 2024-01-15T10:30:00Z and copy the Unix seconds or milliseconds row. Prefer a Z or an explicit offset when the exact instant matters; a date-only string may be interpreted as UTC midnight, and a casual date string may follow the browser's local rules.
Starting from “now”
With an empty input, the table is labeled Current time and shows the instant from when the tool loaded. Use Now writes that same instant as Unix seconds into the input so you can convert it like any other value. The display does not keep ticking; refresh the page if you need a newer “now”.
How conversion works
The input is trimmed. If it is all digits, the page applies the seconds-versus- milliseconds heuristic described above and builds a Date. Otherwise it passes the string to the browser's Date constructor. A failed parse shows an error. A successful parse fills six rows: Unix seconds (the millisecond value divided by 1,000 and floored), Unix milliseconds, toISOString() (always UTC with a Z), the selected-zone clock via Intl.DateTimeFormat, toUTCString(), and the weekday in that zone. Each row has a copy control.
The timezone dropdown starts at UTC and includes sixteen IANA names. Changing the zone updates the “Local time” and weekday rows only; the Unix and ISO rows stay on the same instant.
1705314600
Unix (seconds) 1705314600
Unix (milliseconds) 1705314600000
ISO 8601 2024-01-15T10:30:00.000Z1705314600 is 10:30 UTC on 15 January 2024. The milliseconds row is that value times 1,000. If you had pasted 1705314600000 instead, the page would treat it as milliseconds because it is greater than 1e12, and you would get the same instant.
2024-01-15T10:30:00Z
is the same instant as the Unix seconds value 1705314600Pasting the ISO form and pasting the Unix seconds should agree, as long as the string includes the Z or an offset. That is the safest way to move between the two representations on this page.
What this tool does not do
It does not list every IANA timezone, keep a live ticking clock, or parse fractional Unix values. It does not add or subtract durations. Informal date strings are browser-dependent. Nothing is sent to a server.
How to use Timestamp Converter
- Paste a Unix timestamp (seconds or milliseconds) or an ISO date into the input. Leave it empty to see the time from when the page loaded.
- Choose a timezone from the list if you need a clock reading other than UTC.
- Copy any row you need. Use Now to fill the input with the loaded instant as Unix seconds, or Clear to return to the current-time view.
Frequently asked questions
How does the page decide whether a number is seconds or milliseconds?
If the input is all digits, values greater than 1,000,000,000,000 (1e12) are treated as milliseconds. Smaller numbers are treated as Unix seconds and multiplied by 1,000. Ordinary 10-digit timestamps fall on the seconds side; 13-digit timestamps fall on the milliseconds side. Decimal numbers are not accepted as Unix values and go through the date-string parser instead, which usually fails.
What happens when the input is empty?
The table shows the time from when the tool was loaded, under the heading Current time. Use Now pastes that same instant as Unix seconds into the input so you can work from it. The clock does not tick every second; reload the page or paste a new value if you need a later instant.
Can I convert across any timezone?
No. The timezone list is a fixed set of common IANA names: UTC, several North American and European zones, Dubai, Kolkata, Shanghai, Tokyo, Seoul, Sydney, and Auckland. The default is UTC. The “Local time” row is the time in the selected zone, not necessarily your browser’s zone, and it is formatted with a 24-hour en-US date style.
Which date strings are accepted?
Anything the browser’s Date constructor can parse, including ISO 8601 strings such as 2024-01-15T10:30:00Z. Other informal date strings may work, but the result depends on the browser and can be in local time rather than UTC. Prefer an ISO string with a Z or an offset when you need a precise instant.
What if the input cannot be parsed?
An “Invalid timestamp or date string” message appears. The table may still show the loaded current time underneath that error until you enter a value that parses. Clear the field to go back to the current-time heading.
Is my input sent to a server?
No. Parsing and formatting run in your browser. Closing the tab discards what you typed.
What are the output rows?
Unix seconds, Unix milliseconds, an ISO 8601 string in UTC (toISOString), the time in the selected zone, a UTC string (toUTCString), and the weekday in the selected zone. Each row can be copied individually.
Related tools and guides
References
- Unix time counts seconds (or milliseconds) since 1970-01-01T00:00:00Z. This page shows both units and converts between them and a Date value in the browser.
- Date and Intl.DateTimeFormat are the APIs used to parse strings and format the selected timezone.
- IANA time zone names such as
Asia/Shanghaiare what the dropdown uses. Only the listed zones are available here.