Time Unit Converter
Professional time unit converter supporting fast conversion between milliseconds, seconds, minutes, hours, days, weeks, months, years and more.
Basic time units
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How to use the Time Unit Converter
This tool converts between milliseconds, seconds, minutes, hours, days, weeks, months, years and various extended or high-precision time units. All conversions run entirely in your browser; no data is uploaded, making it safe for logs, uptime calculations and production scheduling scenarios.
- Type a value into any time unit input (decimals and scientific notation are supported). The value is interpreted as a duration in that unit.
- Once you finish input, all other time unit inputs will be updated with the corresponding converted values, allowing you to compare different granularities at a glance.
- Inputs must be numbers greater than or equal to 0. When the input is empty or invalid, other fields are cleared to avoid confusion.
- Months are calculated as 30.44 days on average and generic "years" as 365.25 days. Julian year, leap year and Gregorian year use their respective day definitions.
- High precision units (microsecond, nanosecond, picosecond, femtosecond) are represented as floating point numbers; decimal places and scientific notation are chosen automatically based on magnitude.
- Paste support and auto-select behavior make it easy to copy values from logs, monitoring dashboards or documentation for quick conversion.
FAQ
Why are months and years calculated using average days?
Different months have different lengths (28–31 days) and years may be leap or common years. To perform continuous conversions on a unified time axis, this tool uses average lengths for "month" and "year" (1 month ≈ 30.44 days, 1 year ≈ 365.25 days), which is a common convention in many scientific and engineering contexts.
What is the difference between leap year, Gregorian year and Julian year?
A leap year is treated as 366 days, a Gregorian year as 365 days, and a Julian year as 365.25 days. They are used as different approximations of year length in calendrical calculations, astronomy or engineering, and this tool exposes them as separate units for clarity.
Why do some results show many decimals or scientific notation?
Extreme conversions can easily produce very large or very small numbers. To preserve enough precision while keeping results readable, the converter automatically chooses a suitable number of decimal places or switches to scientific notation for certain ranges.
Can I enter negative time values?
Negative durations are not supported in the current version. In most engineering and business scenarios, duration itself is a non-negative quantity. If you need direction information, consider storing sign or "before/after" separately in your business logic.