Days Calculator

Created by Georgi Georgiev
Last updated: Jun 14, 2026

1. How to do days calculations
2. How many days are there between two dates?
• Calendar days
• Weekdays
• Working days
3. How many days until a date
4. How many days since a date
5. Time between dates
6. Adding days to a date

    How to do days calculations

Sometimes you just need to know how many days you have to finish an assignment or how long a trip is going to be. Using the days between dates calculator is easy and quick as long as you have the first and the last date of the period of time you are interested in. You can choose whether to include the last day in the calculations or not.

Example: You need to find out how many days are between June 23rd and September 15th 2026. If you choose to exclude the final day, the result will be 84 days. If you wish to include the last day in the result, this would be 84+1, resulting in 85 days total.

This days calculator can be used to find the number of days between any two calendar dates e.g. days since a date in the past till today, or from a given date till now. For example, the days between Thanksgiving and Independence day or between Halloween and Thanksgiving, or any other date to date questions.

    How many days are there between two dates?

It may look like a simple question, but the answer actually depends on the definition of what is meant by a "day" in the context of the question. There are three most common approaches required in most problems of calculating the time between dates.

Calendar days

With calendar days one needs to simply calculate how many days there are between the given dates. The math is straightforward with the only complications arising when the time span includes the end of one or more years. That complication is factoring in leap years. Leap years are years with an extra day (versus a regular year) and are necessary in order to keep the calendar in alignment with Earth’s revolutions around the Sun, as it takes about 365 days, 5 hours and 48 minutes for Earth to make a full circle. If leap years are not calculated into the calendar, we would lose about 24 days every 100 years ^[3].

Say you are an expecting parent and today is the first day of November. If the due date is before the end of February next year then leap years do not matter, but if it is after that they may. If the following year is a leap one, then there would be one extra day between today and the due date as opposed to if it was a typical year. This days between calculator takes into account leap years automatically and so does our counter for the count of days between two dates.

Weekdays

In some scenarios one is only interested in how many weekdays there are between two dates. This happens in business when one may state a contract term or offer to perform a given service in N weekdays. However, it is more common to state such terms in business days, as discussed below.

Working days

It is common for business contracts to state the execution time for a certain amount of work, or the delivery terms for goods or services in terms of business days, otherwise known as working days or "bank days" in some cases. While it varies by country, in general working days include all weekdays minus any official holidays such as those due to important state or religious holidays.

    How many days until a date

Regardless if talking about calendar days, weekdays, or just working days, counting the days until a particular date is the same as calculating the number of days between two dates. That is, assuming we know the date of the event of interest. The main complication remains that different months have varying number of days. If you're looking to do the math manually, you'll need to advance to the next month every 28, 29, 30 or 31 days, depending on the particular month, with the remainder in the end being the particular date of the final month you arrive at.

Using our date calculator makes things much easier. Say we have an arrangement for the end of October. To check how many days until October 31, simply enter today's date (August 17, 2026) in the first field and October 31 in the second.

Days until date

The table below features a quick reference for upcoming dates.

For example, to see how long until August 31, 2026 just look up its row to see the time from today until that date.

    How many days since a date

Calculating how long it has been since a date in the past requires calendar calculations just like the ones for checking how many days are from today to a date in the future. If the date is very recent, the number of days since can be worked out via simple subtraction. For example, to count the days from August 5 to August 15 all that is needed is to subtract 5 from 15 to get the result, which is 10.

If the from date and to date fall into different months, you need to take into account how many days each month in between the dates has. It can be 30, 31, 28 or 29 (February in leap years). In such cases a days calculator becomes extremely convenient.

Days since date

The table is a quick reference for the number of days that has elapsed since dates from the recent past.

For example, to see how many days have passed since August 3, 2026 check its row to see the time from that date to today.

    Time between dates

For larger time periods, in some cases it is easier to first do the calculation in days, then convert the result to weeks, months, years, or centuries. In other cases it is easier to work with the desired time interval directly.

Weeks between dates

Starting from the number of days between the dates, it is very easy to find the number of weeks between them since a week has a strict definition that does not change depending on the calendar time. Simply divide the number of days by seven. For example, if our days calculator says there are 28 days between two dates, the number of weeks is calculated as 28 / 7 = 4 full weeks.

Months between dates

To find out the number of months between two dates, one needs to consider the order in which months duration changes, as well as leap years. Some months have 31 days, others have 30 days, and February has either 28 or 29 days depending on it being a leap year or not. For more details see our months between dates calculator.

Years between dates

The number of years between any two dates is a bit easier to calculate. A year has either 365 days for a regular year or 366 days for a leap year. You can use a leap year calculator to count the number of leap years between the dates.

To calculate the number of years from the days between the dates:

1. Multiply the number of leap years by 365
2. Subtract the result from the number of days
3. Divide the remaining number by 365 and add it up with the number of leap years

The most straightforward interface for such tasks is in our how many years calculator.

    Adding days to a date

This calendar days calculator can be used to add any number of calendar days to a starting date. If you input a negative number of days to add, it will instead subtract that many days from the specified date. For adding business days, see our business days calculator which skips weekends and also official holidays in a specified country.