Convert between Unix timestamps and human-readable dates in both directions.
Unix Timestamp
1,700,000,000sec
Tue Nov 14 2023 22:13:20 GMT+0000 (Coordinated Universal Time)
Seconds1,700,000,000
Milliseconds1,700,000,000,000
ISO 86012023-11-14T22:13:20.000Z
UTC StringTue, 14 Nov 2023 22:13:20 GMT
Unix timestamps represent the number of seconds since January 1, 1970 (UTC). The "Date & Time" field uses your local timezone for input.
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What is the Timestamp Converter?
Unix timestamps (also called POSIX time or epoch time) represent a specific moment as a single number—the count of seconds (or milliseconds) that have passed since midnight UTC on 1 January 1970. A timestamp converter bidirectionally translates these numbers into readable dates and times in your local timezone or UTC, and vice versa.
How it works
The tool takes a timestamp (in seconds or milliseconds) and calculates the corresponding calendar date by adding that duration to the epoch date (1 Jan 1970 00:00:00 UTC). It then adjusts for your timezone offset to show the local time. Conversely, when you input a date and time, it calculates how many seconds or milliseconds have elapsed since the epoch to produce the timestamp.
Timestamp (seconds) = (Year − 1970) × 31,536,000 + (Day of year) × 86,400 + (Seconds since midnight)
This simplified formula counts total seconds from the epoch. The exact calculation accounts for leap years and timezone offsets. Millisecond timestamps multiply the seconds result by 1,000.
Examples
Input
Result
Notes
1609459200 (Unix timestamp, seconds)
1 January 2021 00:00:00 UTC
A common reference point; exactly 51 years after the epoch
1704067200 (Unix timestamp, seconds)
1 January 2024 00:00:00 UTC
Y2K24 reference; used in system logs and scheduling
14 January 2025 10:30:45 UTC
1736853045 (Unix timestamp, seconds)
Converting a readable date back to timestamp for API calls
How to use the Timestamp Converter
Enter a Unix timestamp (in seconds, milliseconds, or nanoseconds) or a calendar date with time
Select whether your input is a timestamp or a date—and specify the unit (seconds vs milliseconds)
Choose your timezone (UTC, local, or a specific offset like +05:30)
Click Convert and the tool displays the opposite format instantly
Copy the result to use in logs, API requests, database queries, or configuration files
Benefits
Debug logs and API responses that use timestamps without manually calculating dates
Work across multiple timezones without confusion—see UTC and local time side by side
Generate timestamps for scheduled tasks, cron jobs, and event scheduling
Avoid off-by-one and leap-year errors that crop up in manual calculation
Speeds up development—no need to write conversion code or use a calculator
Understand system time across JavaScript, Python, Go, C, and other languages that all use Unix time
Tips & common mistakes
Common mistakes
Confusing seconds with milliseconds—1609459200 (seconds) is not the same as 1609459200 (milliseconds), which is in 1970
Forgetting timezone offsets—a UTC timestamp is different from the same number interpreted in your local time
Assuming all systems use seconds; some APIs (JavaScript, Java) default to milliseconds
Ignoring leap seconds; Unix time does not account for leap seconds, so timestamps are not perfectly continuous
Tips
Bookmark or pin this tool—you'll use it daily when debugging distributed systems and cloud logs
Timestamps starting with '16...' are typically 2020–2050; starting with '15...' are 2017–2019; use this as a sanity check
When working with APIs, always confirm whether they return seconds or milliseconds; multiply or divide by 1,000 if needed
Store dates as timestamps in databases for consistency; convert to human format only in your UI
Frequently asked questions
Why is 1 January 1970 the start?
It was chosen as a neutral reference point for the Unix operating system. The era is sometimes called the 'Unix epoch' or 'Y2K for Unix.'
What's the difference between a timestamp in seconds and milliseconds?
Milliseconds give finer resolution (1,000 × more precise). JavaScript uses milliseconds; Unix utilities often use seconds. Divide or multiply by 1,000 to convert.
Can I convert very old dates, like 1969 or earlier?
Yes—these produce negative timestamps. For example, 1 January 1960 is −315,619,200 seconds. However, many systems don't support negative timestamps.
Why do some timestamps look so large (13 digits)?
Those are millisecond timestamps, not seconds. A 10-digit number is almost always seconds; 13 digits is almost always milliseconds.
How do leap years affect timestamps?
The converter accounts for them automatically. Every 4 years (except century years not divisible by 400), one extra day is added, shifting all subsequent timestamps.
Can I use this offline?
Many browsers cache this tool. If not, similar converters are built into most programming languages (e.g., Python's `datetime`, Node's `new Date()`).