Time Converter Online Free
Convert between nanoseconds, microseconds, milliseconds, seconds, minutes, hours, days, weeks, months, and years instantly. No signup, runs entirely in your browser.
⏱ 6 min read · Complete guide below
All Time Conversions
| Unit | Value |
|---|---|
| Nanosecond (ns) | — |
| Microsecond (μs) | — |
| Millisecond (ms) | — |
| Second (s) | — |
| Minute (min) | — |
| Hour (hr) | — |
| Day (d) | — |
| Week (wk) | — |
| Month (avg) (mo) | — |
| Year (yr) | — |
How to Convert Time
- 1Select the source unit from the From dropdown — e.g. hours.
- 2Enter your value. The target unit result updates instantly. Use the swap button to reverse direction.
- 3The all conversions table shows the value in every supported unit simultaneously.
Time Units from Nanoseconds to Years
Time measurement spans many orders of magnitude. Computing uses nanoseconds (CPU cycles, memory latency) and milliseconds (network latency, animation frames). Human activities use seconds, minutes, and hours. Calendar calculations use days, weeks, months, and years. The converter handles all these with a single input. Note that months and years use standard averages (30.4375 days/month, 365.25 days/year) to account for calendar irregularities.
Why Months and Years Are Approximations
Seconds, minutes, hours, days, and weeks are exact and fixed — a week is always precisely seven days. Months and years are the awkward ones. Calendar months vary from 28 to 31 days, and a year is not a whole number of days at all: the Earth takes about 365.2425 days to orbit the Sun, which is why we insert a leap day almost every four years to keep the calendar aligned with the seasons. For that reason this converter uses sensible averages — a Julian year of 365.25 days and a month of one twelfth of that (30.4375 days) — so conversions involving months and years are consistent and account for leap years on average. For exact date arithmetic, such as counting the days between two specific calendar dates, use a dedicated date calculator instead, since the answer depends on which particular months are involved.
Time in Computing and Science
The smaller units on this converter matter most in technology and science. Computers operate on nanoseconds — a 3 GHz processor completes a clock cycle in about a third of a nanosecond, and in that time light travels only about 30 centimetres. Milliseconds govern the experiences we notice: network latency under 20 ms feels instant in a game, a 60 fps display refreshes every 16.7 ms, and human reaction time sits around 200 ms. Move up the scale and you reach the human world of seconds, minutes, and hours, then the calendar world of days, weeks, and years. Being able to jump across this vast range — from a billionth of a second to decades — in one input is exactly what makes a general-purpose time converter useful for programmers, scientists, and students alike.
Everyday Time Conversions
Beyond the extremes, most people reach for a time converter for practical, everyday sums: how many hours are in a work week, how many minutes a long process will take, or how many days make up a billing period. A few anchors are worth remembering — an hour is 3,600 seconds, a day is 86,400 seconds, and a standard 40-hour work week is 2,400 minutes. For anything less memorable, entering the value and reading the full conversion table is faster and less error-prone than multiplying by 60 in your head, and it works offline once the page has loaded.
Time Unit Conversion Reference
| Unit | In Seconds | Example |
|---|---|---|
| 1 Nanosecond | 0.000000001 s | CPU clock cycle ~0.33 ns |
| 1 Millisecond | 0.001 s | Human blink ~150 ms |
| 1 Second | 1 s | — |
| 1 Minute | 60 s | 60 × 1 s |
| 1 Hour | 3,600 s | 60 min × 60 s |
| 1 Day | 86,400 s | 24 hr × 3,600 s |
| 1 Week | 604,800 s | 7 × 86,400 s |
| 1 Month (avg) | 2,629,800 s | 365.25 ÷ 12 × 86,400 s |
| 1 Year (Julian) | 31,557,600 s | 365.25 × 86,400 s |
Quick Time Conversion Tips
Hours to Minutes
Multiply by 60. So 2.5 hours = 150 minutes. Reverse: divide minutes by 60 to get hours. 90 minutes = 1.5 hours = 1 hour 30 minutes.
Days to Hours
Multiply by 24. 7 days = 168 hours. A common year = 8,760 hours. A leap year = 8,784 hours. Useful for SLA and uptime calculations.
Milliseconds in Computing
Network latency under 20 ms is excellent for gaming. API response times under 200 ms feel instant to users. A 60 fps display refreshes every ~16.7 ms.
Months and Years
Not all months are equal (28–31 days). For exact date arithmetic use a calendar tool. For approximate calculations, 1 month ≈ 4.35 weeks or 30.44 days.
Frequently Asked Questions
How many seconds are in an hour?
One hour = 60 minutes × 60 seconds = 3,600 seconds. One day = 24 hours = 86,400 seconds. One week = 604,800 seconds.
How many days are in a month?
The converter uses an average month of 30.4375 days (365.25 days ÷ 12), which accounts for leap years. In the Gregorian calendar, months range from 28 to 31 days, so this is an average for calculation purposes.
How many seconds are in a year?
The converter uses a Julian year of 365.25 days = 31,557,600 seconds. This accounts for leap years. The exact length varies: a common year = 31,536,000 s, a leap year = 31,622,400 s.
What is a millisecond?
One millisecond (ms) = 0.001 seconds = 1/1000 of a second. Milliseconds are used in networking (ping/latency), audio production, and sports timing. Human reaction time is typically 150–300 ms.
What is a nanosecond?
One nanosecond (ns) = 0.000000001 seconds (10⁻⁹ s). CPU clock speeds are measured in nanoseconds — a 3 GHz processor completes a clock cycle every ~0.33 ns. Light travels about 30 cm in one nanosecond.
Does the converter work offline?
Yes. All conversion factors are built into the page. After it loads, you can use the converter without an internet connection.
How do I convert a decimal time like 2.75 hours into minutes?
Multiply the decimal by 60. So 2.75 hours = 2.75 × 60 = 165 minutes, which is 2 hours and 45 minutes. The decimal part represents a fraction of the larger unit: 0.75 of an hour is three quarters of 60 minutes, or 45 minutes. This converter accepts decimal input directly, so you can type 2.75 and read the result in any unit without doing the multiplication yourself.
Why isn't a year exactly 365 days?
Because the Earth's orbit around the Sun takes about 365.2425 days, not a whole number. That extra roughly quarter-day is why we add a leap day (February 29) almost every four years — otherwise the calendar would slowly drift out of sync with the seasons. This converter uses a Julian year of 365.25 days so that year and month conversions account for leap years on average.
How many hours are in a work week or a work month?
A standard full-time work week is 40 hours (2,400 minutes). Over a month, full-time work is commonly estimated at about 173 hours, based on 40 hours per week times 4.33 weeks per month. These figures are widely used for payroll, capacity planning, and hourly-rate calculations, though actual hours vary with holidays and the specific number of working days in a given month.
What is the difference between a Julian year and a calendar year?
A Julian year is a fixed length of exactly 365.25 days, used in astronomy and for consistent calculations. A calendar year is either 365 days (common year) or 366 days (leap year) depending on the specific year. This converter uses the Julian year for its year conversions so results are stable and account for leap years on average, rather than depending on which particular year you have in mind.