Free Date & Time Calculators
Count the time between dates without getting lost in calendars. Find your exact age, the number of days, weeks and months between two dates, or how long is left until a birthday, holiday or deadline.
3 free tools
Which date calculator do I need?
Need your exact age for a form, a milestone or just curiosity? The age calculator gives your age in years, months and days, the total days you have lived and a countdown to your next birthday.
Measuring a period between two dates, such as a notice period, a project or a loan term? The date difference calculator counts the days, weeks, months and years between them, with options to include the end date and count business days only.
Looking forward to an event or working toward a deadline? The days until calculator shows how many days, weeks and hours are left, with a live countdown.
How our date calculators handle the calendar
Calendar math is full of small traps. Months have 28 to 31 days, February gains a day in leap years, and a year is a leap year only if it is divisible by 4, unless it is a century year not divisible by 400. Our calculators follow the full Gregorian rules, so ranges that cross February or span many years come out right.
Calculations are based on calendar dates rather than hours, which avoids off-by-one errors when clocks change for daylight saving time. Ages and differences in months are counted in whole calendar months, the way people normally describe them, with leftover days shown separately. For the reasoning behind these methods, read our guide on how to count the days between two dates.
Anything that depends on today's date uses the clock on your own device, so the results match your local time zone.
Tips for accurate date calculations
Decide whether to include the end date before you start. A standard difference from Monday to Friday is 4 days, while an inclusive count, used for things like event days or hotel stays measured in days on site, is 5.
Business day counts exclude weekends but not public holidays, which vary by country and region, so subtract those yourself. If you are turning a period into a cost, such as paying a contractor for a number of working days, the salary to hourly calculator helps convert pay rates between hours, days and years.
Frequently asked questions
How many days are there in a year?
A common year has 365 days and a leap year has 366. Leap years occur every four years, except century years such as 2100, which are skipped unless they are divisible by 400 like 2000.
Does the date difference include the start and end date?
By default the result counts the days between the two dates, which excludes one end. Turn on the option to include the end date if you need every calendar day counted, which adds one day to the total.
How is age calculated for someone born on 29 February?
Our age calculator treats 28 February as the birthday in non-leap years and uses 29 February as normal in leap years. Legal conventions vary by country, and some use 1 March instead, so check the rule that applies if the date matters for official purposes.
Why might my countdown differ from another website?
Differences usually come from time zones, whether today is counted, or whether the end date is included. Our tools use your device's local date and state clearly what is being counted.