Convert time units — seconds, minutes, hours, days, weeks, months, years.
| Unit | Name | Value |
|---|---|---|
| ms | Millisecond | 604800000 |
| s | Second | 604800 |
| min | Minute | 10080 |
| hr | Hour | 168 |
| d | Day | 7 |
| mo | Month (30d) | 0.23333333 |
| yr | Year | 0.019178082 |
Formula: Day = Week × 7
Multiply any week value by 7 to get day.
Reverse: Week = Day × 0.1429
Common week values — factor: 1 wk = 7 d
| Week (wk) | Day (d) | Context |
|---|---|---|
| 1 wk | 7 d | One week |
| 2 wk | 14 d | Two weeks |
| 4 wk | 28 d | One month |
| 8 wk | 56 d | Two months |
| 13 wk | 91 d | One quarter |
| 26 wk | 182 d | Half year |
| 52 wk | 364 d | One year |
| 104 wk | 728 d | Two years |
| 260 wk | 1,820 d | 5 years |
| 520 wk | 3,640 d | One decade |
| 1,040 wk | 7,280 d | 20 years |
| 2,600 wk | 1.82e+04 d | 50 years |
| 5,200 wk | 3.64e+04 d | One century |
| 1.04e+04 wk | 7.28e+04 d | 200 years |
| 5.2e+04 wk | 3.64e+05 d | One millennium |
Weeks × 7 = days. Exact.
1 wk = 7 d, 4 wk = 28 d, 52 wk = 364 d.
Days ÷ 7 = weeks.
Plans two-week sprint cycles and tracks velocity in story points per week.
Structures the academic year into teaching weeks and holiday blocks.
Prescribes treatment durations and follow-up schedules in weeks.
Designs weekly workout plans and measures fitness progress week by week.
Works to weekly publication deadlines and measures subscription periods in weeks.
Tracks notice periods, probation periods, and holiday entitlements in weeks.
The 7-day week has no astronomical basis — unlike the day, month, or year. Its origin is traced to Babylonian astronomy (assigning planets to days) and Jewish tradition (the biblical 7-day creation), later adopted by Rome and spread globally.
The week is the standard unit for work schedules, academic timetables, and business cycles across virtually every culture. The ISO 8601 standard defines Monday as the first day of the week.
Interesting fact: The French Revolutionary Calendar (1793–1805) attempted a 10-day week (décade). It was deeply unpopular and abandoned within 12 years.
The day (86,400 seconds) is defined by Earth's rotation period relative to the Sun. Ancient civilizations independently divided the day into 24 hours — Egyptians used sundials and water clocks as early as 1500 BCE.
Days are the fundamental unit of the Gregorian calendar and human biological rhythm (circadian cycle). Stock markets, shipping logistics, medication dosing, and agricultural planning all operate on daily cycles.
Interesting fact: A 'sidereal day' (Earth's rotation relative to stars) is 23 hours 56 minutes 4 seconds — about 4 minutes shorter than the 24-hour solar day we use.
Converting week to day is a common task across science, engineering, and everyday planning. The time scale spans from nanoseconds in computing to centuries in history, and having accurate conversions helps when comparing measurements across different systems or disciplines.
As a quick reference: 5 wk = 35 d and 10 wk = 70 d. For the reverse: 1 d = 0.1429 wk. The exact conversion factor is 1 wk = 7 d.
All conversions are performed in IEEE 754 double-precision arithmetic, accurate to at least 8 significant figures.