# How to calculate dates.(Microsoft Excel)

06/23/2024

Japanese version.

Here are some formulas to calculate the date of the next day, the day before, etc.

## Steps

### Formulas

#### Next day (N days later), previous day (N days before)

To calculate future dates, add days to the date. (+2 means 2 days later)

To calculate a date in the past, subtract days from the date. (-2 means 2 days before)

#### Next month (after N months), previous month (before N months)

Use the YEAR, MONTH, DAY, and DATE functions.

``=DATE(YEAR(datetime),MONTH(datetime) + Number of months ,DAY(datetime))``

Adding the number of months results in N months later, and subtracting the number of months earlier results in N months earlier.

Normal calculation is performed even if the year-end and New Year holidays are crossed.

The EDATE function may be more convenient for months with different number of days.

#### Next year (N years later), Previous year (N years before)

Similar to the month calculation, but adds/subtracts to the result of the YEAR function.

``=DATE(YEAR(datetime) + Number of years ,MONTH(datetime),DAY(datetime))``

#### Weekday

How to display the day of the week automatically from the date.

#### First day of the month

Specifying 1 in the date portion of the DATE function sets the first day of the month.

``=DATE(YEAR(datetime),MONTH(datetime),1)``

#### End of month (last day of the month)

The first day of the following month is given and one day before the first day is calculated.

``=DATE(YEAR(datetime),MONTH(datetime)+1,1)-1``