Please enter a positive time value.
Enter a decimal number (e.g. 1.5 for 1.5 hours)
⏱️ Quick facts: 1 day = 86,400 sec | 1 week = 168 hours | 1 year = 31,557,600 sec.
Converted Value
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Sources & Methodology
All time unit conversions use exact SI definitions. 1 minute = 60 seconds exactly. 1 hour = 3,600 seconds exactly. 1 day = 86,400 seconds exactly. Month and year averages use standard calendar conventions.
NIST — The Second (SI Unit)
Official definition of the second as the SI base unit of time; all other time units derive from it
BIPM — The International System of Units (SI)
Defines the second and the derived time units used in this calculator
Methodology: All inputs converted to seconds first. 1 minute = 60 s. 1 hour = 3,600 s. 1 day = 86,400 s. 1 week = 604,800 s. 1 month = 30.4375 days = 2,629,800 s (average Gregorian month). 1 year = 365.25 days = 31,557,600 s (Julian year, used by astronomy and NIST for general calculations). HH:MM:SS format: hours = floor(total seconds/3600), minutes = floor((remainder)/60), seconds = remainder mod 60.
⏱ Last reviewed: April 2026
Time Unit Conversion Guide 2026
Time is measured using the second as its SI base unit, from which all larger units are derived by exact multiples. Minutes, hours, and days are defined exactly. Months and years require averages because calendar months vary from 28 to 31 days, and years vary between 365 and 366 days due to leap years. This calculator uses the average Gregorian month (30.4375 days) and the Julian year (365.25 days) for consistent results.
Exact Conversion Factors
1 minute = 60 seconds | 1 hour = 3,600 seconds
1 day = 86,400 s | 1 week = 604,800 s | 1 month (avg) = 2,629,800 s | 1 year (avg) = 31,557,600 s
Full Conversion Table
| Unit | Seconds | Minutes | Hours | Days |
|---|---|---|---|---|
| 1 Minute | 60 | 1 | 0.01667 | 0.000694 |
| 1 Hour | 3,600 | 60 | 1 | 0.04167 |
| 1 Day | 86,400 | 1,440 | 24 | 1 |
| 1 Week | 604,800 | 10,080 | 168 | 7 |
| 1 Month (avg) | 2,629,800 | 43,830 | 730.5 | 30.4375 |
| 1 Year (avg) | 31,557,600 | 525,960 | 8,766 | 365.25 |
Decimal Hours to HH:MM:SS
Decimal hours are commonly produced by time-tracking software and spreadsheets. To convert to hours, minutes, and seconds: the integer part is the hours; multiply the decimal by 60 to get minutes; multiply the minute decimal by 60 to get seconds. For example, 2.75 hours = 2 hours, 0.75 × 60 = 45 minutes, 0 seconds = 2:45:00. For 3.5167 hours: 3 hours, 0.5167 × 60 = 31 minutes, 0.0 × 60 = 0 seconds = 3:31:00.
Common Time Conversions
- 90 minutes = 1.5 hours = 5,400 seconds
- 2 hours 30 minutes = 150 minutes = 9,000 seconds
- 48 hours = 2 days = 172,800 seconds
- 10,000 hours = 416.67 days = 1.14 years (the “mastery threshold”)
- 1,000,000 seconds = 11.57 days = 277.78 hours
- 1 billion seconds ≈ 31.69 years
💡 Timesheet tip: Convert decimal hours to HH:MM by multiplying the decimal part by 60. 7.75 hours = 7 hours 45 minutes. 8.333 hours = 8 hours 20 minutes. Most payroll software requires decimal hours, while client invoices often show HH:MM.
Frequently Asked Questions
3,600 seconds. 1 hour = 60 minutes x 60 seconds = 3,600 seconds exactly (SI definition).
86,400 seconds. 1 day = 24 hours x 60 minutes x 60 seconds = 86,400 seconds exactly.
Multiply hours by 60. 2.5 hours = 150 minutes. 3 hours 45 minutes = (3 x 60) + 45 = 225 minutes. 0.25 hours = 15 minutes.
Divide by 60. 90 minutes = 1.5 hours. For HH:MM format: 90 / 60 = 1 hour and 30 minutes. 150 minutes = 2 hours 30 minutes.
168 hours. 1 week = 7 days x 24 hours = 168 hours exactly. 604,800 seconds or 10,080 minutes.
Multiply the decimal part by 60. For 2.75 hours: 2 hours + (0.75 x 60) = 2 hours 45 minutes. For 8.333 hours: 8 hours + (0.333 x 60) = 8 hours 20 minutes.
Using the Julian year average (365.25 days): 365.25 x 86,400 = 31,557,600 seconds. For a standard 365-day year: 31,536,000 seconds. For a leap year (366 days): 31,622,400 seconds.
1,440 minutes. 1 day = 24 hours x 60 minutes = 1,440 minutes exactly.
Divide by 24. 72 hours = 3 days. 36 hours = 1.5 days = 1 day 12 hours. 100 hours = 4.167 days = 4 days 4 hours.
Hours = floor(seconds / 3,600). Remaining seconds after hours. Minutes = floor(remaining / 60). Seconds = remaining mod 60. For 5,400 s: 1 hour 30 minutes 0 seconds. For 7,384 s: 2 hours 3 minutes 4 seconds (2:03:04).
52 weeks and 1 day (52.1429 weeks) in a standard year, or 52 weeks and 2 days in a leap year. The commonly used average is 52.18 weeks per year.
Decimal hours = hours + (minutes / 60) + (seconds / 3,600). For 2:30:00 = 2 + 30/60 = 2.5 hours. For 1:45:30 = 1 + 45/60 + 30/3600 = 1.7583 hours.
365 days in a standard year, 366 in a leap year. The average Gregorian year is 365.2425 days. The Julian year used in astronomy is 365.25 days exactly.
10,000 hours = 600,000 minutes = 36,000,000 seconds = 416.67 days = 59.52 weeks = 1.14 years. At 8 hours per day, it takes about 3.4 years to accumulate 10,000 hours of practice.
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