Time Unit Converter
Enter any time value, choose its unit, and pick the unit you want to convert it to. The result updates instantly, with a full breakdown showing every conversion in parallel from nanoseconds to centuries.
Formula
Worked example
1 hour to minutes: 1 × (3600 s/h) ÷ (60 s/min) = 60 min. 2.5 years to days: 2.5 × 365.25 = 913.125 days.
How the converter works
Every unit of time can be expressed as a fixed number of seconds, which acts as the universal "base" unit. To convert from one unit to another, the tool multiplies your value by the ratio of those two factors. For example, one hour equals 3,600 seconds and one minute equals 60 seconds, so converting 1 hour to minutes gives 1 × 3,600 / 60 = 60 minutes. Because the factors are fixed ratios, every direction of conversion is equally precise.
Which year length does this tool use?
This calculator adopts the Julian calendar average of 365.25 days per year. That is the standard used by most scientific and engineering tools because it accounts for the leap-year cycle without the additional corrections in the Gregorian calendar (which averages 365.2425 days). For most practical purposes the difference is negligible: a 1-year window differs by only about 10 minutes between the two conventions. A month is defined as 365.25 / 12 days, or roughly 30.4375 days. If you need calendar-exact month or year counts, a date-difference calculator that works with real calendar dates will be more accurate.
Practical time conversions at a glance
A few conversions that come up often: 1 day is exactly 86,400 seconds or 1,440 minutes. 1 week is 168 hours. 1 hour is 3,600 seconds. 1 millisecond is one-thousandth of a second, used in network latency and audio processing. 1 microsecond (one-millionth of a second) appears in CPU timing. 1 nanosecond (one-billionth of a second) is typical in electronics and fiber-optic signal travel times. At the other end of the scale, 1 decade is 10 Julian years and 1 century is 100 Julian years.
Sub-second units: milliseconds, microseconds and nanoseconds
Three units below the second are especially common in technology. A millisecond (ms) is 1/1,000 s and is the standard unit for network round-trip latency: a typical broadband ping of 20 ms means a signal takes 20 thousandths of a second to travel to a server and back. A microsecond (us) is 1/1,000,000 s and describes the cycle time of modern CPUs: a 1 GHz processor completes one cycle per nanosecond and roughly one instruction per microsecond. A nanosecond (ns) is 1/1,000,000,000 s - light travels about 30 cm in one nanosecond, which is why chip designers and network engineers track propagation delays at this level.
Decades and centuries in perspective
A decade (10 years) equals roughly 3.156 × 10^8 seconds, and a century (100 years) roughly 3.156 × 10^9 seconds. These scales appear in long-term financial projections, climate models, demographic forecasts, and historical analysis. When calculating compound interest or population growth across decades, working in consistent base units prevents errors that arise from mixing calendar years of slightly different lengths.
Time unit conversion reference
| Unit | Symbol | Seconds equivalent |
|---|---|---|
| Nanosecond | ns | 0.000000001 |
| Microsecond | us | 0.000001 |
| Millisecond | ms | 0.001 |
| Second | s | 1 |
| Minute | min | 60 |
| Hour | h | 3,600 |
| Day | d | 86,400 |
| Week | wk | 604,800 |
| Month | mo | 2,629,800 |
| Year | yr | 31,557,600 |
| Decade | decades | 315,576,000 |
| Century | centuries | 3,155,760,000 |
Exact and standardised conversion factors. 1 year = 365.25 days (Julian average). 1 month = 365.25/12 days.
Frequently asked questions
How many seconds are in a day?
Exactly 86,400 seconds. A day has 24 hours, each hour has 60 minutes, and each minute has 60 seconds: 24 × 60 × 60 = 86,400.
How many minutes are in a year?
Using the Julian average of 365.25 days per year: 365.25 × 24 × 60 = 525,960 minutes. With a strict 365-day year the answer is 525,600 minutes.
How many milliseconds are in a second?
1,000 milliseconds. The prefix "milli" means one-thousandth, so 1 ms = 0.001 s and 1 s = 1,000 ms.
How many hours are in a week?
168 hours. A week has 7 days and each day has 24 hours: 7 × 24 = 168.
Why does this converter use 30.4375 days per month instead of 30 or 31?
Calendar months have between 28 and 31 days, so there is no single exact value. The standard scientific convention is to divide the Julian year (365.25 days) by 12, which gives 30.4375 days per month. This produces consistent, repeatable results for any conversion involving months, and it matches the average used by most engineering and scientific tools.
Can I convert nanoseconds to years?
Yes. Enter your nanosecond value, select "Nanoseconds (ns)" as the From unit, and select "Years (yr)" as the To unit. The tool divides the value by 31,557,600,000,000,000 (the number of nanoseconds in a Julian year). For very large or very small numbers the result is shown in scientific notation.