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.
Dog Years to Human Years, Explained
Convert dog years to human years the modern way. Why the times-seven rule is wrong, and a quick table for small to giant dogs.
Read guideHow Much of the Year Is Left?
How much of the year is gone, as a percentage, and how much is left. Here is the plain sum and a live bar you can share or embed.
Read guideHow to Add a Countdown Timer to Your Website
Add a live countdown to any site with one paste. How the embed works, what it counts to, and how it keeps ticking for every visitor.
Read guideHow to Add a Days-Since Counter to Your Website
Add a live count-up to any site with one paste. How the embed works, what it counts from, and how to theme it.
Read guideHow to Calculate Your Half-Birthday
Your half-birthday is six months after your birthday. How to work it out, and the leap-day and month-end cases to watch.
Read guideHow to Read Military Time
Military time runs on a 24-hour clock, so 2:30 PM is 1430. Here is how to read it, convert both ways, and a full 0000 to 2300 chart.
Read guideHow Many Days Are in Each Month
Seven months have 31 days, four have 30, and February has 28 or 29. Here is the list, the knuckle trick, and the leap-year rule.
Read guideHow Many Days Until My Birthday?
Count the full days from today to your next birthday. Here is the method, plus how a 29 February birthday is handled.
Read guideHow Many Weeks Until a Date
Count the days until the date, then divide by seven. The whole number is the weeks; the remainder is the leftover days. Here is the method and the edge cases.
Read guideHow to Calculate Hours Between Two Times
Subtract start from end, and add a day when the shift crosses midnight. Here is the method plus how to get decimal hours for a timesheet.
Read guideHow to Find the Moon Phase for Any Date
Measure the time since a known new moon against the 29.53-day lunar month. Here is how the eight phases are worked out and how accurate the result is.
Read guideHow to Find Your Chinese Zodiac Sign by Year
The animal comes from your birth year, paired with an element and a polarity. Here is the cycle and the lunar new year date to watch for.
Read guideHow to Find Your Zodiac Sign by Birth Date
Your star sign comes from the month and day of your birthday. Here are the twelve date ranges and how dates on a boundary are handled.
Read guideHow to Tell If a Year Is a Leap Year
Divides by 4, except century years, which must divide by 400. Here is the leap-year rule with worked examples like 1900 and 2000.
Read guideWhat Day of the Year Is It?
The day of the year counts from 1 January, running 1 to 365 or 366. Here is how to find it and how a leap year shifts dates after February.
Read guideHow 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.
Read guideSkip the reading, just use the tools
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