## Explanation

Dates in Excel are serial numbers that start on 1/1/1900, which is represented by the number 1. In the example shown, the formula in cell D6 simply subtracts the numeric value of 1/1/1999 (36161) from the numeric value of 1/1/2000 (36526) to get a result of 365. The steps look like this:

```
=C6-B6
=36161-36526
=365
```

### Working with today

To count the number of days between an earlier date and today, you can use the TODAY function:

```
=TODAY()-earlier_date
```

To calculate the number of days between a later date and today, use:

```
=later_date-TODAY()
```

Note that TODAY will recalculate on an ongoing basis. If you open the workbook at a later date, the value used for TODAY will update and you will see a new result.

### The DAYS function

The DAYS function calculates the number of days between two dates using a start date and an end date. With a start date in A1 and end date in A2:

```
=DAYS(A2,A1)
```

Will return the same result as:

```
=A2-A1
```

Both dates must be valid Excel dates or text values that can be coerced to dates. If start and end dates are reversed, DAYS will return a negative number.

### Workdays between dates

The formulas above count *all days* between two dates, to calculate *working days* between dates, see the NETWORKDAYS function or NETWORKDAYS.INTL function. See this article for more details.