Guides
Practical date how-tos, no fluff.
Clear, step-by-step guides to the date questions people actually look up: your exact age, the days between two dates, counting business days, ISO week numbers and more. Each one is backed by a free calculator that runs entirely in your browser.
How to Count the Days Between Two Dates
Subtract the earlier date from the later one, then decide whether the end day counts. Here is how to do it without off-by-one errors.
Read guideHow to Calculate Your Exact Age in Years, Months and Days
Count whole years, then months, then leftover days against the real calendar. Here is the method, with the leap-year and 29 February rules.
Read guideHow to Count Business Days Between Two Dates
Count the weekdays in the range and drop every Saturday and Sunday. Here is the method, plus how to add business days to a date.
Read guideHow to Find the Day of the Week for Any Date
Use a calculator or a mental algorithm to get the weekday of any date, plus how to find the third Monday or last Friday of a month.
Read guideWhat Is an ISO Week Number, and How Is It Calculated?
ISO weeks start on Monday and week 1 contains the year's first Thursday. That single rule explains week 53 and the odd start-of-year weeks.
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