Quick start
- Use Date to timestamp mode when you have a UTC date and time.
- Use Timestamp to date mode when you have Unix seconds or milliseconds.
- Choose the correct unit before converting a timestamp.
Best uses
Use this guide when a log, API response, database field, or JavaScript Date value needs a UTC sanity check before you copy the timestamp somewhere else.
- Convert a UTC date and time into Unix seconds for logs or APIs.
- Convert Unix seconds or milliseconds into an ISO UTC timestamp.
- Check whether a timestamp is seconds or milliseconds.
- Compare date-time values without local time-zone ambiguity.
What this converter helps with
The Unix Timestamp Converter is for log, API, database, and developer work where time is stored as a count from the Unix epoch. It uses UTC so the conversion does not silently depend on the viewer’s local time zone.
Match each input label on the converter to the UTC date, UTC time, timestamp number, and selected seconds-or-milliseconds unit your log, API, database, or browser code actually uses.
The logic in plain language
In plain language: Date mode reads the entered date and clock time as UTC, uses Date.UTC to count milliseconds since 1970-01-01T00:00:00Z, then divides by 1,000 for Unix seconds. Timestamp mode reverses that by multiplying seconds by 1,000 or reading milliseconds directly before displaying the UTC ISO time. The examples on the page are there so you can compare your inputs with a UTC timestamp example before copying the answer.
For example, 2026-04-30 12:00 UTC becomes 1777464000 Unix seconds or 1777464000000 milliseconds. Converting either value back should land on 2026-04-30T12:00:00.000Z.
How to read the answer
Read the seconds, milliseconds, and UTC ISO lines together. Copy the unit your system expects instead of treating the two timestamp lengths as interchangeable.
- Unix seconds is the common compact timestamp form.
- Milliseconds is often used in JavaScript and browser APIs.
- UTC ISO output shows the converted instant in a readable standard format.
Common mistakes to avoid
Most timestamp bugs are unit or time-zone bugs, so check those two things before changing the date itself.
- Do not mix seconds and milliseconds; millisecond timestamps are 1,000 times larger.
- Do not enter local time unless you have already converted it to UTC.
- Check application-specific time-zone rules before scheduling real events.
One quick UTC walkthrough
Enter 2026-04-30 and 12:00 in date mode. The converter reads that as noon UTC, counts from 1970-01-01T00:00:00Z, and returns 1777464000 seconds.
If another system gives you 1777464000000 milliseconds, switch to timestamp mode, choose milliseconds, and confirm that the ISO result is 2026-04-30T12:00:00.000Z.
- A 10-digit modern timestamp is usually seconds.
- A 13-digit modern timestamp is usually milliseconds.
- The same instant can display as another clock time after an app applies a local time zone.
Research and references
These references help check JavaScript UTC date behavior, time definitions, and ISO 8601 timestamp formatting used by the guide.
Worked examples for Unix Timestamp Converter
1777464000 seconds
2026-04-30T12:00:00.000Z
1970-01-01T00:00:00.000Z
FAQ in plain language
When should I use the Unix Timestamp Converter?
Use it when your task matches one of these common needs: Convert a UTC date and time into Unix seconds for logs or APIs. Convert Unix seconds or milliseconds into an ISO UTC timestamp. It works best when you already know a UTC date and time, or a numeric Unix timestamp with the seconds or milliseconds unit selected.
What is the Unix Timestamp Converter doing with my inputs?
In plain language: Date mode reads the entered date and clock time as UTC, uses Date.UTC to count milliseconds since 1970-01-01T00:00:00Z, then divides by 1,000 for Unix seconds. Timestamp mode reverses that by multiplying seconds by 1,000 or reading milliseconds directly before displaying the UTC ISO time. The examples on the page are there so you can compare your inputs with a UTC timestamp example before copying the answer.
What do the main Unix Timestamp Converter inputs mean?
Date to timestamp mode: Use this when you have a UTC calendar date and UTC clock time and need Unix seconds plus milliseconds. Timestamp to date mode: Use this when you have a stored epoch value and need to read the matching UTC date-time. UTC date: The calendar date is read as UTC, not as your computer or phone time zone. UTC time: The clock time is read as UTC. Convert local times to UTC first when the source time came from a local schedule. Timestamp: Enter the epoch number only. Unix seconds are usually 10 digits for modern dates, while JavaScript-style milliseconds are usually 13 digits. Unit: Choose seconds for compact Unix timestamps and milliseconds for JavaScript Date-style values.
How should I read the Unix Timestamp Converter answer?
Read the headline answer, then check the supporting lines and examples to understand how the calculator got there. If one input changes, rerun the tool and compare the new answer instead of guessing.
What should I double-check before trusting the answer?
The converter uses UTC on purpose. It does not guess your local time zone, daylight-saving rules, database storage format, or event-scheduling rules, so the same timestamp can appear as a different wall-clock time in another app. Check the mode, confirm the time is already in UTC, and make sure you did not paste a millisecond timestamp while seconds is selected.
Are Unix timestamps seconds or milliseconds?
Both show up in real tools. Unix timestamp usually means seconds since the Unix epoch, while JavaScript Date values use milliseconds. For example, 1777464000 seconds and 1777464000000 milliseconds point to the same UTC instant.
Does this converter use my local time zone?
No. It treats the date and time fields as UTC and displays converted timestamps as UTC ISO time. A local app can display the same instant differently after applying its own time-zone rules.
Related tools
- Time Zone Calculator Convert a UTC date and time into a selected IANA time zone.
- Date Calculator Count days between dates or move a calendar date forward or backward.
- Day of the Week Calculator Find the weekday name and ISO weekday number for a calendar date.
Keep exploring
If this guide is close but not exact, these links keep you near the same kind of problem.
- Date & Time Browse the full category for related tools that help with the same job.
- All free tools Search the complete Access Free Tools library by task, category, or tool name.
- All tool and utility guides Find more plain-language examples, logic notes, mistakes, and result explanations.
- Free tool resources Start here when you are not sure which tool page fits.
Privacy and copying results
Recent answers stay visible only while you work in the current browser tab. They are not sent to a server.
Use Copy answer when you want to save the inputs and result in notes, homework, a message, or a project list. Check the units, labels, and limits before copying.