⏱️ Time Converter
Convert between milliseconds, seconds, minutes, hours, days, weeks, months, and years instantly.
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Common Time Conversions
| Input | Unit | Result | Unit |
|---|---|---|---|
| 1 | Hour | 60 | Minute |
| 1 | Day | 24 | Hour |
| 60 | Minute | 1 | Hour |
| 1 | Week | 7 | Day |
| 1 | Year | 365.25 | Day |
| 1000 | Millisecond | 1 | Second |
Popular Conversions
Time Tools
Formula Reference
1 minute = 60 seconds 1 hour = 60 minutes = 3,600 seconds 1 day = 24 hours = 86,400 seconds 1 week = 7 days = 604,800 seconds 1 month ≈ 30.4375 days (Julian average: 365.25 ÷ 12) 1 year ≈ 365.25 days (Julian year — includes leap years) Note: Month and year results are calendar averages, not exact counts. For specific date arithmetic, use a dedicated date calculator.
About Time Conversions
Time is the most universally experienced physical quantity, yet its units span an enormous range — from the millisecond delays in computer networks to the year-long orbits of planets. The second is the SI base unit of time, formally defined since 1967 by the vibrations of cesium atoms rather than by astronomical observations. Above the second, the familiar units — minutes, hours, days — are rooted in ancient astronomy and the human need to coordinate activity across communities.
The 60-second minute and 60-minute hour trace back to Babylonian base-60 mathematics, adopted by Greek astronomers and passed down through Islamic and European scholarship into the modern world. The 24-hour day reflects the ancient Egyptian practice of dividing daylight into 12 hours and nighttime into 12 hours, regardless of season. These choices were convenient for the math of their era and have proven durable enough to survive unchanged for thousands of years.
Months and years introduce an irregular element that simpler units avoid. A calendar year can be 365 or 366 days depending on leap years, and calendar months range from 28 to 31 days. For general conversion purposes, this calculator uses the Julian calendar averages: 1 month = 30.4375 days (365.25 ÷ 12) and 1 year = 365.25 days. These averages are appropriate for most practical calculations but will differ slightly from specific calendar months or years in date arithmetic.
Frequently Asked Questions
How many seconds are in a minute?
There are exactly 60 seconds in one minute. This base-60 system traces back to ancient Mesopotamia and was adopted by Greek astronomers for dividing the hour and degree into equal parts. It has remained the global standard ever since.
How many minutes are in an hour?
There are exactly 60 minutes in one hour, giving 3,600 seconds per hour (60 × 60). The 60-minute hour comes from Babylonian sexagesimal (base-60) arithmetic, which was practical because 60 is divisible by 2, 3, 4, 5, and 6 — useful for equal division without fractions.
How many hours are in a day?
There are exactly 24 hours in a day. This convention originated with ancient Egyptians who divided daylight into 12 hours and nighttime into 12 hours. The total of 24 hours stuck and was later standardized for the mean solar day — the average time for Earth to complete one rotation relative to the Sun.
How many days are in a month?
Calendar months vary: January, March, May, July, August, October, and December have 31 days; April, June, September, and November have 30 days; February has 28 days (29 in a leap year). For conversion purposes, this calculator uses 30.4375 days as the average month — that is 365.25 ÷ 12, accounting for leap years.
How many days are in a year?
A common calendar year has 365 days; a leap year (every 4 years, with century exceptions) has 366. For conversion purposes, this calculator uses 365.25 days as the average year — called the Julian year — which accurately represents the long-run average including the leap year cycle.
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All conversion results are provided for general informational purposes only. Our formulas use internationally recognized conversion factors; however, rounding may affect precision. Do not rely on these results for professional, medical, legal, or engineering decisions without independent verification. Read our full disclaimer.