Time Converter
Months and years use average lengths (365.25 days/yr).
Quick Reference
Time Unit Conversions Table
Exact conversion factors between the most common time units:
| Unit | Seconds | Minutes |
|---|---|---|
| 1 millisecond | 0.001 | 0.0000167 |
| 1 second | 1 | 0.01667 |
| 1 minute | 60 | 1 |
| 1 hour | 3,600 | 60 |
| 1 day | 86,400 | 1,440 |
| 1 week | 604,800 | 10,080 |
| 1 month (avg) | 2,629,800 | 43,830 |
| 1 year (avg) | 31,557,600 | 525,960 |
Time in Context
- 1 billion milliseconds ≈ 11.57 days
- 1 million seconds ≈ 11.57 days
- 1 billion seconds ≈ 31.7 years
- A 40-hour work week = 2,400 minutes = 144,000 seconds
- The average human lifespan (79 years) ≈ 2.49 billion seconds
- 1 year ≈ 525,960 minutes (the "seasons of love" from Rent)
- Human reaction time: ~200 ms (roughly 0.2 seconds)
- A light-year is a distance, not a time — but light travels ~300,000 km per second, or ~9.46 trillion km per year
Why Months and Years Are Approximations
Unlike seconds, minutes, hours, days, and weeks — which all have exact, fixed lengths — months and years are irregular:
- Months: Range from 28 days (February in common years) to 31 days. The average month is 30.4375 days (365.25 ÷ 12).
- Years: A common year is 365 days; a leap year is 366. The Julian calendar averages 365.25 days/year. The more precise Gregorian average is 365.2425.
- This converter uses 365.25 days/year for simplicity, which introduces a small error (~11 minutes per year) that's negligible for most purposes.
For calculations involving specific calendar dates — how many days between two dates, how many business days, etc. — use the Date Calculator.
Frequently Asked Questions
How many seconds in a day?
There are exactly 86,400 seconds in one day: 24 hours × 60 minutes × 60 seconds.
How many seconds in a year?
A common year has 31,536,000 seconds (365 × 86,400). A leap year has 31,622,400. This converter uses 31,557,600 (365.25 × 86,400) to account for leap years on average.
Why are months and years approximate?
Calendar months range from 28 to 31 days and years are either 365 or 366 days. This converter uses average values (365.25 days/year, 30.4375 days/month) for consistent results. For exact calculations involving specific dates, use the Date Calculator.
How many minutes in a year?
A common year has 525,600 minutes (365 × 24 × 60). A leap year has 527,040. This is the answer to the famous question from the musical Rent.
What is a millisecond used for?
Milliseconds (ms) are used for measuring computer and network response times, audio timing, and brief physical events. Human reaction time averages about 200–250 milliseconds.