Time Converter

Converts durations across milliseconds, seconds, minutes, hours, days, weeks, months and years. The month here is the calendar average — 30.44 days — and the year the astronomical average of 365.25 days, so mixed-unit estimates come out consistent.

How to use

1. Enter a duration in any unit.
2. Read the equivalents across the rest.
3. Use it in both directions — how many seconds in a week, or how many weeks 10⁶ seconds is.
4. For date-to-date gaps, the day-count calculator handles actual calendars; this tool handles durations.

When you actually need this

• Converting a subscription or contract term between months, weeks and days.
• Translating an SLA or uptime figure — 99.9% is 8.77 hours of downtime a year.
• Turning a millisecond timeout or benchmark into human-readable time.
• Estimating project durations quoted in mixed units.

Which month, which year?

No conversion factor can make months honest — they run 28 to 31 days — so this tool uses 30.44, the average over the calendar cycle, and 365.25 days for the year. Fine for estimates; for contract dates, use real calendars. The 365.25 average is why leap years exist: the extra quarter-day accumulates to one day every four years, with the century corrections Gregorian reform added. Handy anchors: a million seconds is 11.6 days, a billion is 31.7 years — a pair worth knowing whenever big numbers of seconds need intuition.

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FAQ

How precise are the conversion factors in Time Converter?

The factors are the internationally defined exact values — one inch is exactly 25.4 millimetres, one pound is exactly 0.45359237 kilograms, and so on. Results are computed at full floating-point precision and only rounded for display.

Can I convert between metric and imperial units in both directions?

Yes. Enter a value in any field and every other unit updates at once, so the conversion works in either direction without switching modes or pressing a button.

Why does the last decimal place sometimes look off?

Because many conversions are irrational in decimal form and browsers use binary floating point, the final digit can differ by a tiny amount. The displayed value is rounded sensibly for everyday use; for laboratory or engineering work, carry the unrounded figure through your own calculation.