About this calculator
Type a number, choose the unit you have and the unit you want, and this converter gives you the answer at once, along with the same time in every other unit it knows.
Every conversion factor is exact by definition wherever one exists, and each result shows the working so you can check it.
Worked examples
Real numbers, worked out by the same calculator. Press “Use these numbers” to try one above.
90 min to h
- hours (h)
- 1.5 h
- milliseconds (ms)
- 5,400,000 ms
- seconds (s)
- 5,400 s
- days
- 0.0625 days
- weeks
- 0.00892857142857 weeks
- years (yr)
- 0.0001711156742 yr
90 min is 1.5 h.
Show the working
- Change to the base unit (s): 90 min × 60 = 5,400 s.
- Change to h: 5,400 ÷ 3,600 = 1.5 h.
1 yr to days
- days
- 365.25 days
- milliseconds (ms)
- 31,557,600,000 ms
- seconds (s)
- 31,557,600 s
- minutes (min)
- 525,960 min
- hours (h)
- 8,766 h
- weeks
- 52.1785714286 weeks
1 yr is 365.25 days.
Show the working
- Change to the base unit (s): 1 yr × 31,557,600 = 31,557,600 s.
- Change to days: 31,557,600 ÷ 86,400 = 365.25 days.
1,000,000 s to days
- days
- 11.5740740741 days
- milliseconds (ms)
- 1,000,000,000 ms
- minutes (min)
- 16,666.6666667 min
- hours (h)
- 277.777777778 h
- weeks
- 1.65343915344 weeks
- years (yr)
- 0.031688087814 yr
1,000,000 s is 11.5740740741 days.
Show the working
- Change to the base unit (s): 1,000,000 s × 1 = 1,000,000 s.
- Change to days: 1,000,000 ÷ 86,400 = 11.5740740741 days.
How to convert by hand
Every unit of time is a fixed number of seconds: 60 seconds in a minute, 60 minutes in an hour (3,600 s), 24 hours in a day (86,400 s) and 7 days in a week (604,800 s). Multiply by the size of the unit you have, then divide by the size of the unit you want.
A year here is 365.25 days (31,557,600 s), the average year including leap years.
Conversion factors used
Each unit is stored as its size in s. The sizes below are the ones this converter uses.
| Unit | Size |
|---|---|
| milliseconds (ms) | 0.001 s |
| seconds (s) | 1 s |
| minutes (min) | 60 s |
| hours (h) | 3,600 s |
| days | 86,400 s |
| weeks | 604,800 s |
| years (yr) | 31,557,600 s |
Common conversions
| From | To |
|---|---|
| 1 h | 60 min |
| 1 days | 24 h |
| 1 weeks | 168 h |
| 1 days | 1,440 min |
| 1 days | 86,400 s |
| 1 yr | 365.25 days |
| 1 yr | 8,766 h |
| 1 h | 3,600 s |
Why the year is 365.25 days
A calendar year has 365 days, but the Earth takes about 365.25 days to orbit the Sun, which is why there is a leap day every fourth year. This converter uses the average, 365.25 days. For exact gaps between two dates, use the date calculator.
Frequently asked questions
How many seconds are in a day?
There are 86,400 seconds in a day.
How many minutes are in a week?
There are 10,080 minutes in a week.
How many hours are in a year?
An average year has 8,766 hours (365.25 × 24).
How accurate is this converter?
It uses the exact defined factors wherever they exist and shows up to 12 significant digits, so the results are accurate to far more digits than you will normally need.
Formulas tested against hand-worked answers. Last reviewed 29 September 2026. These calculators do arithmetic only; they are not financial, tax or legal advice.