Counting Days and Weeks
Most date-counting disputes come down to one question nobody asked out loud: does the last day count? These guides settle that, then cover ISO week numbers, the years that need 53 of them, and the arithmetic behind adding or subtracting a span from a date.
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19 articles
- How Many Hours Are in a Week? 168 Hours ExplainedA standard week has 168 hours. See the calculation, convert weeks to hours, and understand why daylight saving can create a 167- or 169-hour local week.7 min read
- What Time Will It Be in 8 Hours? Calculation GuideAdd eight hours to any starting time, handle midnight correctly, and check what local date and time it will be eight hours from now.7 min read
- How Many Days Until Christmas? Count It CorrectlyCalculate the number of calendar days until Christmas Day, choose inclusive or exclusive counting, and avoid time-zone and countdown mistakes.7 min read
- How to Add and Subtract Time: Hours and MinutesLearn reliable ways to add or subtract hours and minutes, carry values across 60 minutes, and handle results that cross midnight.8 min read
- How Many Minutes? Convert Hours, Days, and WeeksConvert hours, days, and weeks into minutes with simple formulas, reference values, decimal-hour examples, and elapsed-time tips.7 min read
- How to Add 30 Minutes to a TimeAdd 30 minutes to any clock time, including examples such as 30 minutes after 1:45 and calculations that cross an hour or midnight.6 min read
- What Date Is 30 Days From Yesterday?Thirty days from yesterday is the same as 29 days from today. Learn the rule, see a dated example, and distinguish calendar days from business days.6 min read
- How Many Weekend Days Are There in a Year?A year usually has 104 weekend days, but the total can be 105 or 106. See how the starting weekday and leap years change the answer.7 min read
- How Many Work Weeks Are in a Year?A calendar year spans about 52.14 weeks, but paid work weeks depend on payroll boundaries, leave, holidays, and the employer's definition.7 min read
- How Many Weeks Are in Half a Year?Half a year is roughly 26 weeks, but calendar halves range from 181 to 184 days. Learn the exact answer for different meanings of half a year.6 min read
- How Many Weeks Are in a Leap Year?A leap year contains 52 weeks and 2 days. Learn how those extra days affect weekdays, ISO week numbers, payroll, and scheduling.7 min read
- Inclusive vs Exclusive Date Counting: What's the Difference?Inclusive counting includes one or both boundary dates; exclusive counting omits a boundary. See examples and avoid off-by-one date errors.8 min read
- How to Calculate Your Exact AgeDifferent methods for calculating age, and why your 'age' depends on the calendar system.4 min read
- Understanding ISO Week NumbersHow businesses and schedules use week numbers, and how to calculate them correctly.4 min read
- Counting Down to the New YearDifferent cultures celebrate the new year on different dates — here's the fascinating variety.5 min read
- How to Calculate Days Between Two DatesLearn how to find the number of days between dates, choose inclusive or exclusive counting, and handle leap years, times, and workdays.7 min read
- How to Add or Subtract Days From a DateCalculate a future or past date by adding or subtracting calendar days, weeks, months, or business days without off-by-one errors.7 min read
- How Many Weeks Are in a Year?A common year has 52 weeks and 1 day, while a leap year has 52 weeks and 2 days. Learn why some ISO week-numbering years have week 53.6 min read
- Calendar Week vs Workweek: What Is the Difference?Compare ordinary calendar weeks, ISO week numbers, employer-defined workweeks, and payroll periods using clear examples.7 min read