datetoday.now guides & articles
10 in-depth guides on Date Today and related topics.
Quick answers
Quick answers
Counting Business Days: What Counts And What Does Not
A deadline quoted in business days is shorter than it looks. Here is what counts as a working day, how weekends and holidays come out, and why the answer changes by country.
Quick answers
Days Between Two Dates: How To Count Them Correctly
Counting the days between two dates is simple arithmetic that goes wrong constantly. Here are the inclusive and exclusive rules, and the boundaries that break manual counting.
Quick answers
How Many Days Left In The Year? Work It Out Exactly
The days left in the year is one subtraction away once you know the day of year. Here is the arithmetic, the leap year adjustment, and the inclusive-counting trap.
Quick answers
What's The Date Today? How To Read And Write It
Today's date can be written half a dozen ways, all correct. Here is how to read each one, why they differ, and what else the date tells you about the year.
Calendar facts
Calendar facts
Date Format By Country: Who Writes Dates Which Way
The same six digits mean different days in London, New York and Tokyo. Here is the date format each country uses, and the two ways to write a date that cannot be misread.
Calendar facts
Calendar Systems: Dates In Hijri, Hebrew And Chinese Years
Today has a date in several calendars at once. Here is how the Hijri, Hebrew and Chinese systems are built, and why none of them keeps step with the Gregorian year.
Calendar facts
Day Of Year And Julian Day Number Explained
Every date has a plain ordinal number between 1 and 366. Here is how the day of year is calculated, how 29 February shifts it, and how it differs from a Julian day.
Calendar facts
ISO Week Number Explained: The First-Thursday Rule
Week numbers look simple until the turn of the year, when 1 January can land in week 52 of the year before. Here is the ISO 8601 rule that decides it.
Calendar facts
Leap Year Explained: The Rule, The Reason, The Exceptions
Divisible by four, except centuries, except centuries divisible by four hundred. Here is why that awkward rule exists, and what 29 February does to the rest of the year.
Calendar facts
Week Start: Why Weeks Begin On Monday Or Sunday
Two wall calendars can show the same month with the columns in different orders. Here is why the week start is disputed, who uses which, and what it changes.