Convert Time Units
Enter a value and select the source and target units.
How the Time Units Converter Works
Convert any time unit in four simple steps.
Enter a Value
Type the numeric value you want to convert. Decimals and large numbers are both supported — enter 1.5 days or 86400 seconds.
Select Source Unit
Choose the unit your value is in from the dropdown: seconds, minutes, hours, days, weeks, months, or years.
Select Target Unit
Choose the unit to convert to. The result updates instantly showing the exact equivalent value.
View All Units
Below the main result, see the value converted to every time unit simultaneously — plus a visual comparison bar.
What Is a Time Units Converter?
Understanding time unit relationships and conversion factors.
The time unit hierarchy
Time units form a hierarchy: 1 year = 12 months = 52.18 weeks = 365.25 days = 8,766 hours = 525,960 minutes = 31,557,600 seconds. Each step involves a different multiplier, making mental conversion tricky.
Conversion factors
- 1 minute = 60 seconds
- 1 hour = 60 minutes = 3,600 seconds
- 1 day = 24 hours = 1,440 minutes = 86,400 seconds
- 1 week = 7 days = 168 hours
- 1 month = 30.4375 days (average)
- 1 year = 365.25 days (accounting for leap years)
Why conversion matters
Different contexts need different units. Payroll uses decimal hours. Project management uses days or weeks. Science uses seconds. Being able to quickly convert ensures accuracy across contexts. Switch a clock reading to 24-hour format with the military time converter.
When to Use a Time Units Converter
Common scenarios for time unit conversions.
Scientific Research
Convert experiment durations to seconds (SI unit) for data analysis. Most scientific formulas require time in seconds for consistency.
Project Planning
Convert hours to days or weeks for Gantt charts. If a task takes 120 hours, how many 8-hour work days is that? The answer: 15 work days.
Medical & Dosing
Convert dosing intervals between hours and minutes. Drug administration schedules often switch between units depending on context.
Space & Astronomy
Convert between seconds, hours, and years for calculating orbital periods, light-travel times, or mission durations in space exploration.
Data Analysis
Standardize time data for charts and reports. Convert mixed units (some in hours, some in days) to a single unit for consistent comparison.
Sports Statistics
Convert game times between minutes and hours. How many hours is a 48-minute basketball game? Or a 5-day cricket test match?
Step-by-Step Walkthrough
One value expanded across every unit, showing where the conversions are exact and where they stop being so.
A project manager needs to express a 90-day delivery window in every unit their stakeholders use.
Convert downward to hours
90 × 24 = 2,160 hoursDays to hours is exact: every day contains 24 hours by definition. Conversions moving downward through the units never lose precision.
Running total2,160 hours
Continue to minutes and seconds
2,160 × 60 = 129,600 minutes 129,600 × 60 = 7,776,000 secondsEach step multiplies by 60. These are the units that operational systems, SLAs and monitoring thresholds normally speak in.
Running total7,776,000 seconds
Convert upward to weeks
90 ÷ 7 = 12.857 weeksAlso exact — a week is precisely seven days. The result is not a whole number, but nothing has been approximated to get it.
Running total12.86 weeks
Convert to months — approximately
90 ÷ 30.44 ≈ 2.96 monthsHere precision ends. A month has no fixed length, so the conversion uses an average of 30.44 days. Ninety days from 1 January is 1 April; from 1 June it is 30 August — the same 90 days, different calendar outcomes.
Running total≈ 2.96 months
Convert to years — also approximately
90 ÷ 365.25 ≈ 0.246 yearsThe 365.25 average absorbs leap years. Useful for rough scale, misleading for anything contractual — a "quarter of a year" is not a date anyone can act on.
Running total≈ 0.25 years
Ninety days is exactly 2,160 hours and 12.86 weeks, but only about 2.96 months. The line between exact and approximate falls between weeks and months.
Common Mistakes and Pro Tips
Mistakes that quietly corrupt your numbers
Treating 3 months and 90 days as interchangeable in a contract or deadline.
Use whichever the agreement actually specifies, and calculate the real date from it.
Why it matters: Three months from 30 November is 28 February — 90 days. Three months from 1 March is 1 June — 92 days. The gap swings by several days depending on where in the calendar you start, which is enough to move a deadline.
Using 30 days as a month when converting a long period.
Use the average of 30.44 days, or better, work in exact dates.
Why it matters: The 30-day approximation loses over five days per year. Across a two-year projection that is a fortnight of drift, all of it in the same direction, and it compounds silently.
Rounding 365 for a year in any multi-year calculation.
Use 365.25 to absorb leap years, or count actual dates.
Why it matters: The quarter-day is exactly why leap years exist. Ignoring it costs roughly a day every four years — the same drift that made calendar reform necessary in the first place.
Chaining conversions: seconds to minutes to hours to days, rounding at every hop.
Convert from the original value directly to the unit you want.
Why it matters: Each rounding compounds into the next. Going straight from 7,776,000 seconds to days in one division is exact; the four-step route can be off by hours by the time it arrives.
Pro tips
Know where exactness ends
Seconds, minutes, hours, days and weeks convert exactly between one another. Months and years do not. That boundary is the single most useful thing to remember about time units.
Use dates for anything contractual
If a deadline matters, calculate the actual calendar date rather than a month count. "Three months" is an approximation; 15 April is a commitment.
Memorise three constants
86,400 seconds in a day, 604,800 in a week, 3,600 in an hour. Between them they cover most conversions you will do without a tool.
Convert directly, never in a chain
Go from the source unit to the target in one operation. Every intermediate step is another opportunity to round, and the errors only ever accumulate.
Say which convention you used
When reporting a month or year figure, state the assumption — "≈ 3 months at 30.44 days/month". It makes the number reproducible and stops someone re-deriving a different one.
Match precision to the question
2.96 months is false precision for a planning conversation. Round to "about three months" for people, and keep the exact days figure for the system.
Time Unit Conversion Constants
The multipliers behind every conversion, with exact values distinguished from averages.
| Unit | In seconds | In hours | In days | Exact? |
|---|---|---|---|---|
| 1 second | 1 | 0.000278 | 0.0000116 | Exact |
| 1 minute | 60 | 0.01667 | 0.000694 | Exact |
| 1 hour | 3,600 | 1 | 0.041667 | Exact |
| 1 day | 86,400 | 24 | 1 | Exact |
| 1 week | 604,800 | 168 | 7 | Exact |
| 1 fortnight | 1,209,600 | 336 | 14 | Exact |
| 1 month (avg) | 2,629,746 | 730.5 | 30.44 | Average |
| 1 quarter (avg) | 7,889,238 | 2,191.5 | 91.31 | Average |
| 1 common year | 31,536,000 | 8,760 | 365 | Exact |
| 1 leap year | 31,622,400 | 8,784 | 366 | Exact |
| 1 year (avg) | 31,557,600 | 8,766 | 365.25 | Average |
| 1 decade (avg) | 315,576,000 | 87,660 | 3,652.5 | Average |
No rows match that filter.
Rows marked Average have no fixed length — a month is 28 to 31 days and a year is 365 or 366. Use them for scale, never for deadlines. For an exact span between two calendar dates, use the days between dates calculator.
Why Some Time Units Are Approximate
The calendar is an astronomical compromise, and the conversions inherit it.
A month has no fixed length
Calendar months run from 28 to 31 days, and the pattern does not repeat cleanly because it was never designed to. The average across a full year is 30.44 days, which is the figure used here.
That average is fine for expressing scale — "roughly three months" — and wrong for anything that has to land on a date. Three months from 31 January cannot even be expressed as a date without a further convention about what to do when the target month is shorter.
Where a specific day matters, count dates rather than months. Where only magnitude matters, the average is perfectly serviceable.
Why a year is 365.25 days
Earth's orbital period is about 365.2422 days — not a whole number, and not a convenient fraction either. The Julian calendar approximated it as 365.25 by adding a leap day every four years.
That slightly overshoots, so the Gregorian reform added the exception most people know: century years are leap years only when divisible by 400. Hence 2000 was a leap year and 1900 was not.
For conversions, 365.25 is accurate enough across any human-scale period. The residual error is under a day per century, which no scheduling question is sensitive to.
Leap seconds and why they are ignored here
Atomic time and Earth's rotation drift apart by a fraction of a second per year, and leap seconds have historically been inserted into UTC to keep them aligned. Several dozen have been added since the 1970s.
They matter enormously for satellite navigation, financial timestamping and distributed systems, where a repeated or skipped second can corrupt an ordering.
For unit conversion they are irrelevant — a total of a few dozen seconds across five decades disappears entirely into the rounding of any practical answer. This converter treats every day as exactly 86,400 seconds.
Choosing a unit for your audience
The right unit depends on who is reading, not on what is most precise:
- Seconds — systems, monitoring, service-level thresholds
- Minutes and hours — work, billing, scheduling
- Days and weeks — project planning, delivery windows
- Months and years — strategy and long-range comparison only
Reporting a two-year projection in hours is technically exact and practically useless. Reporting a four-hour outage in months is neither. Match the unit to the decision being made.
Frequently Asked Questions
Common questions about the Time Units Converter.
How many seconds are in a day?
There are exactly 86,400 seconds in a day. The calculation is 24 hours × 60 minutes × 60 seconds = 86,400 seconds. Enter 1 day in the converter to see all equivalent units.
How does the converter handle months?
Months are calculated using the average month length of 30.4375 days (365.25 days ÷ 12 months). This accounts for the varying lengths of calendar months and leap years.
How are years calculated?
Years use 365.25 days per year to account for leap years. This is the standard astronomical Julian year used in scientific calculations.
Can I convert fractional values?
Yes. You can enter decimal values like 1.5 hours or 2.75 days. The converter calculates the exact equivalent in every other unit.
What is the visual comparison bar?
The visual bar shows the relative magnitude of your conversion. It helps you intuitively understand the scale difference between units — for example, 1 year shown as a full bar compared to 525,960 minutes.
Is this converter accurate for scientific use?
For seconds, minutes, hours, and days, the converter is exact. For months and years, it uses standard averages (30.4375 days/month, 365.25 days/year). For precise calendar calculations, use a date calculator instead.
Why is a month shown as approximate?
Because calendar months vary from 28 to 31 days, so no single figure is correct. The converter uses an average of 30.44 days, which is fine for expressing scale but should never be used to calculate a deadline date.
Why use 365.25 days for a year instead of 365?
The quarter-day accounts for leap years, which exist because Earth’s orbital period is roughly 365.2422 days. Using a flat 365 loses about a day every four years, and that drift accumulates in one direction.
Which conversions are exact?
Everything from seconds through to weeks. Seconds, minutes, hours, days and weeks have fixed relationships to each other, so those conversions lose no precision. Months and years are the only approximate units.
Should I convert step by step through the units?
No — convert directly from the source unit to the one you want. Chaining conversions and rounding at each stage compounds the error, whereas a single division or multiplication stays exact.
Does the converter account for leap seconds?
No. Every day is treated as exactly 86,400 seconds. The few dozen leap seconds added since the 1970s are far too small to affect any practical conversion, though they do matter for satellite and financial timing systems.