Time Converter – Seconds, Minutes, Hours, Days and Years

Time units and their definitions

The converter uses the second as its base unit:

• 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 year = 365.25 days = 31,557,600 seconds

The year is the Julian year of 365.25 days, which averages a common year and a leap year. It is the standard choice in astronomy and gives a fair average over several years. A specific calendar year has either 365 or 366 days; use the date difference calculator when you need the exact number of days between two dates.

Decimal hours versus hours and minutes

A result of 1.5 hours means one and a half hours – 1 hour and 30 minutes, not 1 hour and 50 minutes. To turn decimal hours into minutes, multiply the decimal part by 60: 2.75 hours is 2 hours and 45 minutes. Timesheets and payroll often use decimal hours, so this conversion matters when calculating pay. The overtime and salary calculators work with decimal hours for that reason.

Common time conversions

• 90 minutes = 1.5 hours
• 1,000 seconds ≈ 16.7 minutes
• 1 million seconds ≈ 11.6 days
• 1 billion seconds ≈ 31.7 years
• 168 hours = 1 week

Milliseconds in computing

Software, video and network tools often measure time in milliseconds (ms). One second has 1,000 ms; a delay of 250 ms is a quarter of a second. Unix timestamps count seconds since 1 January 1970; the Unix timestamp converter turns them into readable dates.

Durations, not clock times

This converter changes the unit of a duration. To add hours to a clock time or calculate the time between two moments, use the time duration calculator; for different time zones, use the time zone converter.

Sources

Conversion factors follow the SI definitions in the BIPM SI Brochure and the exact factors for US customary and imperial units in NIST Special Publication 811.