Time Converter

1 hour = 3600 s · 1 day = 86400 s · 1 year = 31536000 s

Speed, Time & Data

How to Use This Tool

Time converter

Type a value into any field and the converter calculates the rest. It handles days, hours, minutes, seconds, milliseconds, and weeks. All conversions are exact since time units have fixed relationships, unlike length or weight where rounding is involved.

Common time conversions

From To Multiply by
Hours Minutes 60
Hours Seconds 3,600
Minutes Seconds 60
Days Hours 24
Days Minutes 1,440
Days Seconds 86,400
Weeks Days 7
Weeks Hours 168
Seconds Milliseconds 1,000
Minutes Hours (decimal) 0.01667

Time conversion formulas

Hours to minutes

minutes = hours x 60

Example: 2.5 hours x 60 = 150 minutes.

Minutes to decimal hours

decimal hours = minutes / 60

Example: 45 minutes / 60 = 0.75 hours. This comes up constantly in payroll and billing.

Days to hours

hours = days x 24

Example: 3 days x 24 = 72 hours.

Seconds to hours

hours = seconds / 3,600

Example: 7,200 seconds / 3,600 = 2 hours.

Weeks to minutes

minutes = weeks x 10,080

Example: 2 weeks x 10,080 = 20,160 minutes.

When you need time conversions

Payroll and billing

Timesheets often record hours and minutes, but payroll software needs decimal hours. 7 hours and 45 minutes is 7.75 decimal hours, not 7.45. Getting this wrong means paying employees incorrectly. Freelancers billing in quarter-hour increments need to convert 15 minutes to 0.25 hours, 30 minutes to 0.5, and so on.

Project planning

Estimating a project in hours is common, but communicating deadlines requires converting to days or weeks. A 200-hour project with one person working 8-hour days takes 25 working days, or 5 weeks. With two people, it could take 12.5 working days if the work can be split evenly.

Cooking and baking

Recipes give times in hours, minutes, or both. A slow cooker recipe calling for 6 to 8 hours is 360 to 480 minutes. Converting between these helps when setting timers, especially on devices that only accept minutes.

Science and computing

Response times, latency, and processing speeds are measured in milliseconds or microseconds. A 200 ms response time is 0.2 seconds. A database query taking 50,000 microseconds is 50 milliseconds or 0.05 seconds. These conversions matter when debugging performance.

Common durations for reference

Duration Equivalent
1 minute 60 seconds / 60,000 milliseconds
1 hour 60 minutes / 3,600 seconds
1 day 24 hours / 1,440 minutes / 86,400 seconds
1 week 7 days / 168 hours / 10,080 minutes
1 month (average) 30.44 days / 730.5 hours
1 year (common) 365 days / 8,760 hours / 525,600 minutes
1 leap year 366 days / 8,784 hours / 527,040 minutes
1 decade 3,652.5 days (accounting for leap years)

Tips for accurate conversions

  • When converting minutes to decimal hours, divide by 60, not 100. The most common payroll error is treating 30 minutes as 0.30 hours instead of 0.50 hours. Similarly, 15 minutes is 0.25 hours and 45 minutes is 0.75 hours.
  • Months and years are not fixed time units. A month can be 28, 29, 30, or 31 days. A year is usually 365 days but 366 in a leap year. For precise calculations, convert to days or hours first.
  • Time zones add complexity. “24 hours from now” and “tomorrow at the same time” might be different if a daylight saving time change happens in between. In that case, 24 hours later could be an hour off from “the same time tomorrow.”
  • Unix timestamps count seconds since January 1, 1970. To convert a Unix timestamp difference to hours, divide by 3,600. A difference of 43,200 seconds is 12 hours.

Decimal time and military time

Decimal time expresses partial hours as decimals instead of minutes. 3:30 PM in standard time is 3.5 hours after noon. Payroll, billing, and project management software almost always uses decimal hours because they are easier to add and multiply.

Military time (the 24-hour clock) runs from 00:00 to 23:59. 1:00 PM is 13:00, 6:30 PM is 18:30, and midnight is 00:00. To convert PM times, add 12. To convert back, subtract 12 from any hour above 12. Most of the world uses 24-hour time in daily life, while the US, Canada, and Australia primarily use 12-hour time with AM and PM.

Frequently asked questions

How many seconds in a day?

86,400 seconds (24 x 60 x 60).

How many minutes in a year?

525,600 minutes in a common year (365 x 24 x 60). A leap year has 527,040 minutes.

How do I convert minutes to decimal hours?

Divide the minutes by 60. So 20 minutes is 20/60 = 0.333 hours. For payroll, common values: 15 min = 0.25, 30 min = 0.50, 45 min = 0.75.

How many milliseconds in a second?

1,000 milliseconds = 1 second. One microsecond is 0.001 milliseconds, and one nanosecond is 0.000001 milliseconds.

How many weeks in a year?

52.143 weeks in a common year (365 / 7). That is 52 weeks and 1 day. A leap year has 52 weeks and 2 days.

What is a fortnight?

A fortnight is 14 days, or 2 weeks. The word comes from Old English “feowertyne niht” meaning fourteen nights. It is still used in British, Australian, and New Zealand English.

How long is a fiscal quarter?

A fiscal quarter is roughly 13 weeks or 91 days. The exact length depends on the calendar months in that quarter, ranging from 90 to 92 days.

How do I convert between 12-hour and 24-hour time?

For PM times, add 12 to the hour. 2:30 PM becomes 14:30. For AM times, the hour stays the same except 12:00 AM, which becomes 00:00. To go back, subtract 12 from hours 13 through 23.

Measurement guides

Formula & Explanation

Time conversions are based on the SI second, defined as the duration of 9,192,631,770 cycles of radiation from the transition between two hyperfine levels of the ground state of cesium-133.