Unix Timestamp Converter
Paste timestamps, dates or Excel serials, one per line, and read each one back as ISO UTC, your local time, relative time, Excel serial and Discord code. Runs in your browser — nothing is uploaded.
Current Unix time
Live from your device's clock. Click a value to copy it.
Seconds, milliseconds, microseconds, nanoseconds, Excel serials, ISO 8601, RFC 2822, Discord tags — each line is detected on its own.
One row per line, tab-separated — paste it straight back into the next spreadsheet column.
1735689600Unix seconds- ISO 8601 (UTC)
2025-01-01T00:00:00Z- Local time
- 2025-01-01 00:00:00 UTC, UTC+0
- Excel serial
- 45658
- Seconds
1735689600- Milliseconds
1735689600000- Discord
<t:1735689600:F> <t:1735689600:R>
1735689600123Unix milliseconds- ISO 8601 (UTC)
2025-01-01T00:00:00.123Z- Local time
- 2025-01-01 00:00:00 UTC, UTC+0
- Excel serial
- 45658.00000142
- Seconds
1735689600.123- Milliseconds
1735689600123- Discord
<t:1735689600:F> <t:1735689600:R>
45658Excel serial date- ISO 8601 (UTC)
2025-01-01T00:00:00Z- Local time
- 2025-01-01 00:00:00 UTC, UTC+0
- Excel serial
- 45658
- Seconds
1735689600- Milliseconds
1735689600000- Discord
<t:1735689600:F> <t:1735689600:R>
2025-01-01T12:00:00ZISO 8601- ISO 8601 (UTC)
2025-01-01T12:00:00Z- Local time
- 2025-01-01 12:00:00 UTC, UTC+0
- Excel serial
- 45658.5
- Seconds
1735732800- Milliseconds
1735732800000- Discord
<t:1735732800:F> <t:1735732800:R>
The Excel formulas
Every formula returns UTC. Excel does not know your offset on a given date; the Local time column above does. After the formula, press Ctrl+1 and pick a date format.
- Seconds to date
=(A1/86400)+DATE(1970,1,1) - Milliseconds to date
=(A1/86400000)+DATE(1970,1,1) - Date to seconds
=(A1-DATE(1970,1,1))*86400 - Serial number of 1 January 1970
25569 · =(A1-25569)*86400
Read a timestamp by its digit count
Current values only: a ten-digit number today starts with 17, an Excel serial is five digits, a Windows FILETIME is eighteen. Nine digits are still seconds (1973–2001) and an eight-digit 20250101 is a date, not a timestamp.
| Digits | Read as | Example | ISO 8601 (UTC) |
|---|---|---|---|
| 1–7 | Excel serial date | 45658 | 2025-01-01T00:00:00Z |
| 8 | yyyymmdd date | 20250101 | 2025-01-01T00:00:00Z |
| 9–10 | Unix seconds | 1735689600 | 2025-01-01T00:00:00Z |
| 11–13 | Unix milliseconds | 1735689600123 | 2025-01-01T00:00:00.123Z |
| 14 | SAP timestamp | 20250101120000 | 2025-01-01T12:00:00Z |
| 15–16 | Unix microseconds | 1735689600123456 | 2025-01-01T00:00:00.123456Z |
| 18 | Windows FILETIME | 133801632000000000 | 2025-01-01T00:00:00Z |
| 19 | Unix nanoseconds | 1735689600123456789 | 2025-01-01T00:00:00.123456789Z |
Reference values
The timestamps looked up again and again: zero, the Excel serial of that same day, the billionth second and the last second of 32-bit time.
0 | Unix seconds | 1970-01-01T00:00:00Z |
25569 | Excel serial date | 1970-01-01T00:00:00Z |
1000000000 | Unix seconds | 2001-09-09T01:46:40Z |
2147483647 | Unix seconds | 2038-01-19T03:14:07Z |
Runs in your browser — nothing you paste is uploaded or stored.
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About Unix Timestamp Converter
Confileo's Unix Timestamp Converter tool converts Unix timestamps in seconds, milliseconds, microseconds or nanoseconds, Excel serial dates and written dates into each other, one line at a time, in both directions. Everything runs in your browser, free and without signup, and your files are deleted automatically after processing.
A Unix timestamp counts seconds since 1 January 1970, 00:00:00 UTC, and today's values begin with 17 — 1735689600 is the first second of 2025. They fill log files, API responses, database exports, JWT expiry fields and Discord tags, none readable by eye, which is why an epoch converter is a daily developer tool. This page converts timestamp to date and date to timestamp, both ways live, and runs in your browser: nothing you paste is uploaded.
Detection is per line, not per box. Ten digits are seconds. Thirteen are milliseconds, from JavaScript's Date.now(), Java or Kafka. Sixteen are microseconds, nineteen are nanoseconds from InfluxDB or Python's time.time_ns(). Nine digits are still seconds (March 1973 to September 2001) and a negative value is before 1970. Decimals like 1735689600.123456 keep their fraction. Sixteen- and nineteen-digit values are where most converters go quietly wrong: they exceed 2^53, JavaScript's exact-integer limit, so Number() rounds their last digits away. Here they are handled as text and split into seconds and remainder.
An Excel date is a different number: a serial day count in which 45658 is 1 January 2025, 45658.5 is noon that day, and 25569 is the Unix epoch — the constant behind =(A1/86400)+25569, or =(A1/86400)+DATE(1970,1,1), with 86400000 for milliseconds. A pasted column of serials is recognised line by line. Serials below 61 fall before Excel's phantom 29 February 1900 and come out a day off. Google Sheets and LibreOffice share the same day 0; a Mac 1904-system workbook is 1,462 days lower.
Output is one line per input line, blank lines kept, columns tab-separated, so a column copied out of Excel pastes back into the next column as separate cells: ISO 8601 in UTC, the same instant in your zone with its IANA name and the real offset on that date (Europe/London, UTC+1 in summer, UTC+0 in winter), a relative form such as 3 days ago, the Excel serial, seconds and milliseconds. No spreadsheet formula can supply that offset; Excel does not know when daylight saving began.
Pasted input is rarely clean. A JSON fragment like "created_at": 1735689600, or a log time like [1735689600.123] loses its punctuation, a .NET /Date(1735689600000)/ is read, and a Discord <t:1735689600:R> tag is unwrapped. Every result carries the Discord codes back out, <t:…:F> for a full date and <t:…:R> for a countdown, so an announcement renders in each reader's own zone. Eighteen digits are a Windows FILETIME, the 100-nanosecond count since 1601 behind Active Directory's lastLogon. An eight-digit 20250101 is a date, not a timestamp; as seconds it would be 23 August 1970, which is what most converters return.
Dates going the other way are never guessed. ISO 8601 with a Z or an offset and an RFC 2822 header like Wed, 01 Jan 2025 12:00:00 +0100 are unambiguous. A naked 2025-01-01 12:00 is not, so it is shown twice, as UTC and as your local time, and a slashed 01/02/2025 is read US-style as 2 January on this English page. Anything above 2147483647 — 19 January 2038, 03:14:07 UTC, the end of signed 32-bit time — is flagged as the year 2038 problem.
Quick facts
- Price
- Free — no paywall
- Signup
- Not required
- Max file size
- Up to 100 MB per file
- Your files
- Deleted automatically after processing
- Works on
- Any browser — desktop, tablet, mobile
- Watermark
- None on your output
How to use Unix Timestamp Converter
- 1Paste timestamps, dates or Excel serials into the left box, one per line — each line is detected on its own, so seconds, milliseconds and serials can be mixed.
- 2Read the row for each line: ISO 8601 in UTC, your local time and zone, relative time, Excel serial, seconds, milliseconds and the Discord tag.
- 3Copy the result — the columns are tab-separated, so a pasted spreadsheet column lands back in Excel as separate cells.
Why use Confileo
- ✓100% free with no daily limits, watermarks or hidden paywalls.
- ✓No signup or account required — start using it instantly.
- ✓Your files are processed securely and deleted automatically for full privacy.
- ✓Works in any browser on desktop, tablet and mobile — nothing to install.
- ✓Fast processing built to handle real, everyday document workloads.
Unix Timestamp Converter — Frequently asked questions
How do I convert a Unix timestamp to a date in Excel?
Put the timestamp in A1 and enter =(A1/86400)+DATE(1970,1,1), then press Ctrl+1 and pick a date or custom format such as yyyy-mm-dd hh:mm:ss, because the result is a serial number until you format it. For milliseconds divide by 86400000 instead. The formula gives UTC; Excel knows nothing about your zone or daylight saving, so add the offset yourself or paste the column here and read it from the local-time column.
Is my timestamp in seconds or milliseconds?
Count the digits. A current Unix timestamp in seconds has ten digits and starts with 17; in milliseconds it has thirteen, in microseconds sixteen, in nanoseconds nineteen. JavaScript, Java and Kafka use milliseconds; PHP, Python's time.time(), JWT exp fields and most Unix commands use seconds. The split by digit count stays safe until the year 2286, when ten-digit seconds run out. This page reads each line by its length, so a mixed paste is fine.
Why does my Excel date show as a number like 45658?
Because that number is the date. Excel stores every date as a serial day count in which 45658 is 1 January 2025 and the fraction is the time of day, so 45658.5 is noon. The cell has only lost its date format: select it, press Ctrl+1 and choose a date format. If the number arrived from a CSV and you need the Unix timestamp instead, paste the column here and it is recognised as an Excel serial automatically.
How do I make a Discord timestamp?
Paste the date or timestamp here and copy the Discord column: <t:1735689600:F> shows the full date and time, <t:1735689600:R> shows a countdown such as "in 3 days", and d, D, t, T and f give shorter and longer forms. Discord renders each code in every reader's own time zone, which is why the tag beats typing a time into an announcement. The value between the colons is always seconds, never milliseconds.
What is the year 2038 problem?
Systems that store Unix time in a signed 32-bit integer can count up to 2147483647, which is 19 January 2038 at 03:14:07 UTC. One second later the value wraps negative and reads as December 1901. Modern operating systems and databases use 64-bit time and are unaffected, but embedded devices, old file formats and some C code still are not. This page flags any value above the limit so you can see it at a glance.
Do Unix timestamps count leap seconds?
No. Unix time assumes every day has exactly 86,400 seconds, so the 27 leap seconds inserted since 1972 are not in the count; each one was absorbed by repeating a second rather than adding one. That is why a timestamp and a UTC clock can disagree by a second right at midnight on a leap-second day, and why the difference between two timestamps is not always the true elapsed time. For everything short of astronomy it does not matter.
Is this tool really free?
Yes. Every Confileo tool is free to use with no daily caps, no watermark on your output and no credit card required.
Do I need to create an account?
No. You can use the tool straight away without signing up or logging in.
Are my files safe and private?
Yes. Your files are processed for the task you requested and then deleted automatically — they are never shared or kept.
Does it work on my phone?
Yes. The tool runs in any modern browser, so it works the same on desktop, tablet and mobile with nothing to install.