Instant · Precise · Universal
28 units available
6 categories total
To convert months to days: multiply by 30.44 (average). To convert to weeks: multiply by 4.35 (approximate).
1 average month ≈ 30.44 days ≈ 4.35 weeks ≈ 730.5 hours ≈ 2,629,800 seconds.
For example, 1 Month (Average) (mo) = 0.08333511526 Year (Tropical) (yr (Trop)).
| Month (Average) (mo) | Year (Tropical) (yr (Trop)) |
|---|---|
| 0.1 | 0.008333511526 |
| 0.5 | 0.04166755763 |
| 1 | 0.08333511526 |
| 2 | 0.1666702305 |
| 5 | 0.4166755763 |
| 10 | 0.8333511526 |
| 25 | 2.083377881 |
| 50 | 4.166755763 |
| 100 | 8.333511526 |
| 500 | 41.66755763 |
| 1000 | 83.33511526 |
The average month is a unit of time equal to approximately 30.44 days (2,629,800 seconds), representing 1/12 of a Gregorian calendar year.
1 average month ≈ 30.44 days ≈ 4.35 weeks ≈ 730.5 hours ≈ 2,629,800 seconds.
To convert months to days: multiply by 30.44 (average). To convert to weeks: multiply by 4.35 (approximate).
Billing cycles, rent payments, project milestones, medication tracking, and age calculations (especially for infants).
The mnemonic '30 days hath September' dates to the 13th century. February's 28 days result from Augustus taking a day for August from February.
Treating all months as 30 days. For precise calculations, always account for actual month lengths.
The knuckle trick: make fists, count across knuckles (bumps = 31 days, valleys = 30 or fewer). Start with January on the first knuckle.
The tropical year is the time for the Sun to return to the same equinox point — approximately 365.24219 days (31,556,925.216 seconds).
1 tropical year ≈ 365.24219 days ≈ 365 d 5 h 48 min 45 s. Shorter than the sidereal year by about 20 minutes due to precession.
To convert tropical years to days: multiply by 365.24219. To Julian years: multiply by 365.24219/365.25.
Calendar design — the Gregorian calendar's average year (365.2425 days) approximates the tropical year to within 26 seconds.
The tropical year is slowly shortening — by about 0.53 seconds per century. In the year 1900, it was 365.24220 days.
Confusing tropical year with sidereal year — the tropical year is ~20 minutes shorter due to axial precession.
The tropical year governs seasons. If we used the sidereal year for calendars, seasons would slowly drift through the months over ~26,000 years.



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