Free Online Time Converter
A duration tool maps a value across nanoseconds through years using the second as the SI pivot and a 365.25-day year for the longer-scale conversions.
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How to Use This Converter
- Pick the source unit in From.
- Pick the target unit in To.
- Type the value; the converted duration and factor display.
- Tap swap to flip the conversion direction.
What Is a Time Converter?
Time spans nine orders of magnitude in everyday use, from nanoseconds inside a CPU to years on a project plan. The SI base is the second. Scientific units (ns, μs, ms) are powers of 10. Civil units (min, hr, day, week) follow the inherited 60-60-24-7 ratios. Beyond a week, the conversion has to pick an averaging convention.
This tool uses 30.4375 days for an average month (365.25 / 12) and 365.25 days for a year, which accounts for leap years. That makes it the right choice for project budgets, server uptime and rough age calculations — but not for exact calendar arithmetic, which depends on the start date.
For exact day-by-day calculations between two dates, the dedicated date-difference tool handles the calendar correctly.
Frequently Asked Questions
How many seconds in a day?
What time units are supported?
What about months and years?
Published by the WeGotEveryTool team. We build and test every tool in-house and update pages when the underlying spec, formula, or recommendation changes.
Reviewed: May 2026. Disclaimer: this tool is provided as-is for general informational use. For decisions with material consequences (medical, legal, financial, security) verify results against a qualified professional source.