Time Units Converter
Convert a time value between nanoseconds, milliseconds, seconds, minutes, hours, days, weeks, months and years. Enter any value, pick the source unit, and see the result in every other unit at once.
Convert Time Units
Time Converter Formula
Where:
- \(t_{\text{source}}\) — the time value you entered, in the source unit
- \(k_{\text{source}}\) — number of seconds in one source unit
- \(k_{\text{target}}\) — number of seconds in one target unit
- \(t_{\text{target}}\) — the same time expressed in the target unit
The converter first changes your value into seconds, then divides by the factor of the target unit. The factors used are: nanosecond \(10^{-9}\) s, millisecond \(10^{-3}\) s, second 1 s, minute 60 s, hour 3600 s, day 86 400 s, week 604 800 s, average month 2 629 746 s (30.436875 days), average year 31 556 952 s (365.2425 days).
Time Converter – Calculation Example
Example: convert 2 hours into all other time units.
\[ t = 2 \,\text{h} \times 3600 = 7200 \,\text{s} \]
\[ 7200 \div 10^{-9} = 7.2 \times 10^{12} \,\text{ns} \quad 7200 \div 10^{-3} = 7.2 \times 10^{6} \,\text{ms} \quad 7200 \div 60 = 120 \,\text{min} \]
\[ 7200 \div 86400 = 0.083333 \,\text{d} \quad 7200 \div 604800 = 0.011905 \,\text{wk} \quad 7200 \div 2629746 = 0.002738 \,\text{mo} \quad 7200 \div 31556952 = 0.000228 \,\text{yr} \]
Result: 2 hours = 7 200 000 000 000 ns = 7 200 000 ms = 7 200 s = 120 min = 0.0833 days = 0.0119 weeks = 0.00274 months = 0.000228 years.
How to use the Time Converter
- Enter the quantity you want to convert in the Time Value field (any non-negative number).
- Choose the unit you are converting from in the From Unit dropdown — nanoseconds, milliseconds, seconds, minutes, hours, days, weeks, months or years.
- Read the results under Equivalent Time in All Units: the value is shown in every other unit at once, and the row matching your source unit is hidden automatically.
Very large or very small results are displayed in scientific notation (for example, \(7.2 \times 10^{12}\) nanoseconds), so nothing gets lost to rounding.
What is time unit conversion?
Time unit conversion expresses one duration in a different unit without changing its length. Because the second is the SI base unit of time, the most reliable method is a two-step process: convert the source value to seconds, then convert seconds to the target unit. This avoids memorizing dozens of pairwise factors (minutes to weeks, hours to months, and so on) — you only ever need the seconds-per-unit factor of each unit.
The metric submultiples follow the standard powers of ten: one nanosecond is \(10^{-9}\) seconds and one millisecond is \(10^{-3}\) seconds. If you often work with these prefixes, the Metric Prefix Converter can help you check them. The everyday units are fixed multiples of the second: 60 seconds per minute, 60 minutes per hour, 24 hours per day and 7 days per week.
Months and years are the tricky ones, because their length varies. This calculator uses the average Gregorian values: a year of 365.2425 days (accounting for leap years) and a month of 365.2425 ÷ 12 = 30.436875 days. This is the standard convention for approximate long-duration conversions and gives consistent, reproducible answers.
Converting time units is useful in everyday planning (hours to weeks for a project schedule), in science and engineering (seconds to milliseconds or nanoseconds for signal timing), and in communication (translating a technical duration such as 86 400 seconds into "one day"). Related tools on this site include the Frequency Converter for cycles per unit time, the Download Time Estimator for combining speed and duration, and the Speed Converter when distance per unit time matters.
Assumptions, limitations and tips
- Months and years are averages. A calendar month can be 28 to 31 days, and a year is 365 or 366 days. Results for months and years are approximations based on the Gregorian average; for exact calendar work, count the actual dates instead.
- No negative values. The calculator rejects negative inputs. If you need a time difference that might come out negative, subtract the dates first and convert the absolute difference.
- Decimal input. Fractional values are allowed, so you can enter 2.5 hours or 0.125 days directly instead of pre-converting them yourself.
- Choose a sensible unit. Very large or very small outputs (below \(10^{-6}\) or above \(10^{15}\)) switch to scientific notation. If your result looks unwieldy — say, billions of seconds — pick a larger source unit or convert in the other direction for a friendlier number.
- Rounding. Results are shown with up to 6 decimal places; tiny values keep more precision through scientific notation.
Quick reference table
| Unit | Symbol | Equals (seconds) |
|---|---|---|
| Nanosecond | ns | \(10^{-9}\) |
| Millisecond | ms | \(10^{-3}\) |
| Second | s | 1 |
| Minute | min | 60 |
| Hour | h | 3 600 |
| Day | d | 86 400 |
| Week | wk | 604 800 |
| Month (average) | mo | 2 629 746 |
| Year (average) | yr | 31 556 952 |
Frequently Asked Questions
How do I convert time units by hand without a calculator?
Convert everything through seconds. Multiply your value by the number of seconds in one source unit (a minute has 60, an hour 3600, a day 86 400, a week 604 800), then divide by the seconds in the target unit. For example, 3 days to hours: \(3 \times 86400 = 259200\) seconds, and \(259200 \div 3600 = 72\) hours. With practice you can also use chained shortcuts like \(24 \times 60 = 1440\) minutes per day.
How many seconds are in a day, a week, and a year?
One day is 86 400 seconds (\(24 \times 60 \times 60\)), one week is 604 800 seconds, and one average Gregorian year is 31 556 952 seconds (365.2425 days). A leap year has 31 622 400 seconds. If you only need a rough figure, the popular approximation "about 31.6 million seconds per year" or \(\pi \times 10^7\) seconds is accurate to within half a percent.
Why is a month sometimes 30 days and sometimes 30.44 days?
Calendar months vary from 28 to 31 days, so there is no single fixed factor. This converter uses the average Gregorian month of 30.436875 days (365.2425 ÷ 12), which gives consistent results across many conversions. If you need an exact answer for specific dates — for example, January 1 to February 1 — count the actual days between those dates instead of multiplying by an average.
How do I convert between nanoseconds, microseconds, and milliseconds?
These are metric powers of ten: 1 millisecond = \(10^{-3}\) s, 1 microsecond = \(10^{-6}\) s, and 1 nanosecond = \(10^{-9}\) s. Each step is a factor of 1000, so 1 ms = 1 000 000 ns and 1 ns = 0.000001 ms. Light travels about 30 cm in one nanosecond, which is why chip and network timings are quoted in ns.
What is a common mistake when converting time units?
The most frequent error is assuming 0.5 hours equals 50 minutes — decimal fractions of hours or minutes are not the same as clock notation. 0.5 h is 30 minutes, and 90 minutes is 1.5 hours, not 1:90. Another pitfall is mixing up "a month = 4 weeks" (28 days) with the true average of ~30.44 days; the four-week shortcut drifts by about 2.4 days per month.
How many hours, minutes, or seconds are in a typical work year?
Using the average year of 365.2425 days: 8 765.82 hours, 525 949 minutes, and 31 556 952 seconds. A work year is smaller — for example, 260 working days (52 weeks × 5) at 8 hours per day equals 2 080 hours, or 124 800 minutes. Adjust for holidays, vacation, and part-time schedules to get your actual figure.
Does this converter handle daylight saving time and leap seconds?
No. It converts pure durations, not calendar spans. DST shifts mean a calendar day can be 23 or 25 hours long, and leap seconds occasionally make a minute 61 seconds — this tool always uses the standard 86 400-second day. For scheduling across DST changes or for precision timing applications like GPS, use date-aware tools or consult the relevant standards.