Time Units Converter: Seconds, Minutes, Hours & Days
Convert between seconds, minutes, hours, days, weeks, and years instantly. Supports clock time input (HH:MM:SS), decimal and scientific notation, and precision up to 8 decimal places. Perfect for payroll, project management, software development, and scientific calculations.
Convert Time Units
Enter Time
Quick Select
Input Value:
3600.0000 seconds
1 hour, 0 minutes
Conversion Results
3600.0000
60.0000
60 min, 0 sec
1.0000
1 hr, 0 min
0.0417
0 days, 1 hr
01:00:00
Hours : Minutes : Seconds
0.1250
Based on standard 8-hour workday
Quick Reference
Time Context
Visual Scale
Real-world Comparisons
Common Time Intervals
Professional Tips
- • Use 4+ decimal precision for payroll to avoid rounding accumulation
- • Unix timestamps count seconds from Jan 1, 1970 — divide by 3600 for hours
- • 1 work day = 480 minutes = 8 hours; 1 work week = 2400 minutes
- • Clock time input (HH:MM:SS) avoids manual seconds multiplication
- • Enable scientific notation for values above 1 million seconds
Last updated: May 11 2026
Reviewed by the QuickTooly Team
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Time Units Converter Guide
How to Convert Between Time Units
All time units derive from the second — the SI base unit for time. The relationships are fixed: 1 minute = 60 seconds, 1 hour = 3,600 seconds, 1 day = 86,400 seconds, 1 week = 604,800 seconds, and 1 year ≈ 31,557,600 seconds (365.25 days to account for leap years). To convert any unit, first multiply to seconds, then divide by your target unit's seconds-per-unit constant.
For example: 90 minutes → seconds: 90 × 60 = 5,400 s → hours: 5,400 ÷ 3,600 = 1.5 hours. This tool performs all conversions simultaneously from a single input, saving you from chaining multiple manual calculations.
Time Conversion Formulas & Reference
Seconds ↔ Other Units
Minutes = Seconds ÷ 60 | Hours = Seconds ÷ 3,600 | Days = Seconds ÷ 86,400 | Weeks = Seconds ÷ 604,800 | Years = Seconds ÷ 31,557,600
Minutes ↔ Other Units
Seconds = Minutes × 60 | Hours = Minutes ÷ 60 | Days = Minutes ÷ 1,440 | Work Days (8 hr) = Minutes ÷ 480
Clock Time (HH:MM:SS)
To decode clock time: total seconds = (hours × 3600) + (minutes × 60) + seconds. To encode: hours = floor(total ÷ 3600), remaining minutes = floor((total mod 3600) ÷ 60), remaining seconds = total mod 60.
Decimal vs. Clock Notation
Decimal hours (1.75 hr) are ideal for payroll and billing calculations. Clock notation (01:45:00) is universal for display. To convert: 0.75 hours × 60 = 45 minutes → 01:45:00.
Practical Use Cases
- Payroll & Timesheets: Convert worked minutes to decimal hours for billing. 97 minutes = 1.6167 hours at your hourly rate. Use 2-decimal precision for billing, 4+ decimals for internal tracking.
- Software Development: Unix timestamps are seconds since Jan 1, 1970. Convert API response durations (milliseconds) to human-readable units. Calculate timeout and cache TTL values across units.
- Project Management: Translate task estimates between minutes (granular) and days (planning). 480 minutes = 1 work day (8 hours), 2,400 minutes = 1 work week.
- Scientific & Engineering: Use scientific notation for extreme values (nanoseconds to centuries). Maintain consistent unit standards throughout datasets to avoid conversion errors.
Understanding Precision & Scientific Notation
Choosing the Right Precision
2 decimals are sufficient for general human scheduling. 4 decimals work for most payroll and billing. 6–8 decimals are for scientific measurements, performance benchmarks, or microsecond-accurate timing.
When Scientific Notation Helps
For values ≥ 1,000,000 or smaller than 0.001, scientific notation prevents digit overload. 1 year ≈ 3.16 × 10⁷ seconds is clearer than 31,557,600.000000. Enable "Scientific Notation" or "Both Formats" in the Display Format selector above.
Leap Years & Calendar Accuracy
This tool uses 365.25 days/year (the Gregorian average) for year conversions — accurate for rough calculations. For exact date arithmetic, use a dedicated date calculator that accounts for specific leap years.
Frequently Asked Questions
How many seconds are in a day?
86,400 seconds exactly: 24 hours × 60 minutes × 60 seconds = 86,400.
How do I convert 90 minutes to hours?
90 ÷ 60 = 1.5 hours, or 1 hour and 30 minutes (01:30:00 clock time).
How many minutes are in a day?
1,440 minutes exactly: 24 × 60 = 1,440. For a work day (8 hours): 480 minutes.
How many seconds are in a year?
Approximately 31,557,600 seconds (using 365.25 days). A non-leap year has 31,536,000 s; a leap year has 31,622,400 s.
What is 3600 seconds in minutes and hours?
3,600 seconds = 60 minutes = 1 hour exactly.
How do I convert clock time to decimal hours?
Divide the minutes by 60 and add to the hours: 2:30 = 2 + (30 ÷ 60) = 2.5 decimal hours. For HH:MM:SS, also divide seconds by 3600: 1:30:45 = 1 + 30/60 + 45/3600 ≈ 1.5125 hours.
How do I convert milliseconds to seconds?
Divide by 1,000: 1,500 ms ÷ 1,000 = 1.5 seconds. Programming environments like JavaScript (Date.now(), performance.now()) return time in milliseconds, making this conversion common in web and software development.