# DATEDIF

The `DATEDIF` function in Google Sheets calculates the difference between two dates using a specified unit of measurement. This function is commonly used to calculate the length of time between two dates, such as the number of days, months, or years. The function is particularly useful when working with financial or project planning data.

## Usage

Use the `DATEDIF` formula with the syntax shown below, it has 3 required parameters:

Parameters:
1. start_date (required):
The starting date of the time period to calculate. This must be a valid date in Google Sheets, such as a cell reference or a date enclosed in quotation marks.
2. end_date (required):
The ending date of the time period to calculate. This must be a valid date in Google Sheets, such as a cell reference or a date enclosed in quotation marks.
3. unit (required):
The unit of measurement to use when calculating the time period. This must be one of the following values: "D" for days, "M" for months, or "Y" for years.

## Examples

Here are a few example use cases that explain how to use the `DATEDIF` formula in Google Sheets.

### Calculate age

The `DATEDIF` function can be used to calculate a person's age based on their birthdate and the current date. By specifying the unit as "Y", the function will return the number of years between the two dates.

### Calculate project duration

When planning a project, the `DATEDIF` function can be used to calculate the length of time between the start and end dates. By using different units, such as "M" for months or "D" for days, the function can provide different levels of detail in the calculation.

### Calculate billing period

Invoicing and billing systems can use the `DATEDIF` function to calculate the length of time between billing periods, such as the number of days between two invoices. By specifying the unit as "D", the function will return the number of days between the two dates.

## Common Mistakes

`DATEDIF` not working? Here are some common mistakes people make when using the `DATEDIF` Google Sheets Formula:

### Incorrect date format

The formula won't work if the date format is incorrect. Ensure that the dates are entered in a valid format, such as 'dd/mm/yyyy'.

### Wrong order of dates

The start date should be entered before the end date in the formula. Check that the dates are entered in the correct order.

### Incorrect unit

The third argument in the formula should be one of the valid units: 'Y', 'M', or 'D'. Ensure that the correct unit is used.

The following functions are similar to `DATEDIF` or are often used with it in a formula:

You can learn more about the `DATEDIF` Google Sheets function on Google Support.