How many days between two dates?
Pick a start date and an end date: the big number is the count of days from one to the other. The start day is not counted and the end day is: from Monday to Friday is 4 days, and from January 1 to December 31 of the same year is 364 days. If you need to count both ends, as for a hotel stay counted in days rather than nights or an event that runs from the first to the last day, add 1.
Under the result, the same span is written three more ways: in weeks and days, in years, months and days, and in weekdays (Monday to Friday). The calculator remembers your dates on this device, and the tool works for any date between 1900 and 2100.
Add or subtract days, weeks, months or years
Switch to “Add or subtract” to find a date: a start date, plus or minus a number, and a unit. The result shows the date, its weekday and how far it is from today. Typical uses: a due date 90 days after an invoice, a deadline 30 days after a notice, the date 6 weeks before an event.
Days and weeks are simple: they add exactly. Months and years follow the calendar: the result keeps the same day number. When that day does not exist, the calculator uses the last day of the month, so January 31 plus one month is February 28 (29 in a leap year), and February 29, 2028 plus one year is February 28, 2029. That is why “plus 1 month” and “plus 30 days” can give different answers.
How many days until a date?
Leave the first date on today (the Today button resets it) and set the second date to the day you are waiting for: a trip, a birthday, a due date. The big number is the number of days left, or “in the past” if the date has gone by. For Christmas, the Christmas countdown counts down to the second, and the countdown works for any event.
Weekdays and business days
The detail line counts weekdays, Monday to Friday, between the two dates, not counting the start date. It does not know about public holidays, which vary by country and state. For working days that skip holidays, use the business days calculator. As a rule of thumb, 5 weekdays make one calendar week, 10 make two, and 20 make four.
Days in each month
| Month | Days | Day of year on the 1st |
|---|---|---|
| January | 31 | 1 |
| February | 28 (29 in a leap year) | 32 |
| March | 31 | 60 (61) |
| April | 30 | 91 (92) |
| May | 31 | 121 (122) |
| June | 30 | 152 (153) |
| July | 31 | 182 (183) |
| August | 31 | 213 (214) |
| September | 30 | 244 (245) |
| October | 31 | 274 (275) |
| November | 30 | 305 (306) |
| December | 31 | 335 (336) |
The knuckle trick: make two fists and count the months over your knuckles and the dips between them. Knuckles are 31-day months, dips are the shorter ones. A year has 365 days, or 366 in a leap year: every year divisible by 4, except years ending in 00 that are not divisible by 400.
Counting days by hand
To count the days between two dates without a calculator, add three pieces: the days left in the first month, the full months in between, and the day number in the last month. From March 10 to June 25: 21 days left in March, 30 in April, 31 in May, plus 25 in June, which makes 107 days. The same method works across years, adding 365 or 366 for each full year.
Common durations
| Days | In weeks | Date from today |
|---|---|---|
| 7 | 1 week | 7 days from today |
| 14 | 2 weeks | 14 days from today |
| 30 | 4 weeks and 2 days | 30 days from today |
| 60 | 8 weeks and 4 days | 60 days from today |
| 90 | 12 weeks and 6 days | 90 days from today |
| 180 | 25 weeks and 5 days | 180 days from today |
| 365 | 52 weeks and 1 day | 365 days from today |
Watch the date format
Many date mistakes come from reading a date the wrong way, not from counting. In the US, 03/04/2027 means March 4. In the UK, France and most of the world, the same digits mean 3 April. When a date comes from abroad, an invoice, a ticket or a contract, check the order before you count, or look for the month written in words. The international standard, ISO 8601, writes the year first, then the month and the day: 2027-04-03. It sorts correctly in spreadsheets and file names and cannot be misread, which is why software and travel systems use it.
The same care applies to “next Friday” or “this weekend” in a message sent late at night: write the full date when it matters.
Things that trip people up
- “Within 30 days” of what? Most deadlines start counting the day after the event. Check whether the rule counts calendar days or business days, and what happens when the last day is a weekend.
- Months are not 30 days. A “3-month” deadline can be 89 to 92 days long.
- Time zones do not matter here. The calculator counts calendar days on your device, so clock changes and time zones never shift the result.
- Old dates. All dates use today’s Gregorian calendar. For weekdays of historical dates, see the day of the week calculator.
To find your exact age in years, months and days, use the age calculator; to work with hours and minutes rather than days, the time calculator.