What would you do when you want to know the days between two dates according to the rule of “12 months a year, 30 days a month, and 360 days a year”? For example, you are an accountant who need to deal with the payment (eg. interest). Don’t be a fool to list each month and add up all the days!

In Microsoft Excel, once you input the start date and end date, you can directly get the days between them in just seconds. The only thing you need is the Days360 formula.

It’s easy to learn how to use Days360 in Excel—Just follow me!

## How To Use the Days360 Formula To Calculate Days in Excel

DAYS360(start_date,end_date,[method])

Days360 formula requires 3 parameters, you need to input the start date, and end date, and choose the method of U.S. or European. For a simple example, I will teach you how to calculate the days between 2011-01-01 with 2011-01-30 in the following steps.

**Step1-Input the dates in the Date formula.**

We need to use a Date formula to input the start date and end date. Here we search for the Date formula.

And the syntax of Date formula is: DATE(year, month, day).

In this formula, it is straightforward to input the number of the year(2011), month(1), and day(1). Then we can get a correct date format for the start date. And it is the same for the end date.

When we finish inputting your start date and end date, we can see that the start date is at A1, and end date is at A2, like this:

**Step2-Input the dates in the Days360 formula.**

Here we search for the Days360 formula.

And the syntax of the Days360 formula is: DAYS360(start_date,end_date,[method]).

We can just click the start date(A1) and end date(A2) in order.

**Step3-Choose the method.**

The last thing we need to do is to choose the U.S. method or European method.

Method | Definition |

FALSE or omit | U.S. (NASD) method. If the start date is the last day of a month, it is equal to the 30th of the same month. If the end date is the last day of a month and the start date is earlier than the 30th, then the end date equals the 1st of the following month, otherwise, the end date equals the 30th of the month. |

TURE | European method. If the start date and end date are the 31st of a month, they are equal to the 30th of the month. |

After we choose the method(here choose FALSE), we can directly get the days between 2011-01-01 with 2011-01-30 in just seconds and the result is 29.

## What if I Just want to know the exact days?

If you don’t have to obey the rule of “12 months a year, 30 days a month, and 360 days a year” and just want to get an exact result of how many days there are between two dates, then Days360 Formula maybe not suitable for you. You need to learn another formula: Days Formula.

Example:

I will calculate the days between 2011-02-01 and 2011-03-01. And as we all know, there is imposible 30 days in February. So let’s see the results showed in Days360 Formula and Days Formula.

Yes, we can see that Days Formula can give you an actual days between the given dates. But Days360 Formula is always set up with the rule of “30 days a month”.

## Why Do I Get the Wrong Result in Days360 Formula in Excel?

**Error1**

Under normal circumstances, we get a positive result. If we get a negative result, then we can recheck the input order of the start date and end date whether it is inverse.

**Error2**

We are required to input the start date and end date in the date-time format in excel, that is why we need the Date formula. If we input it as text format, it will generate errors.

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