# Excel Functions

An Excel **Function** is a **Predefined Formula** with a human-friendly name.

For example, **=A3+B3+C3** is an Excel formula used in the cell **D3**. This formula will return the sum of values in the cells A3, B3 and C3 into the cell D3.

Instead of entering this formula with addition operator **(+)**, we can use the predefined formula in Excel for adding values. This predefined formula is called **SUM Function**.

**=SUM(A4,B4,C4)** will return the sum of values in the cells A4, B4 and C4.

Functions can handle individual cells as well as data ranges.

**=SUM(A5:C5)** will return the same result of **=SUM(A5,B5,C5)**

Similarily AVERAGE function can be used to find out the average of values in a data range or multiple data ranges.

There are more than **450** functions in Excel and the following are the most popular ones.

**SUM**, **IF**, **LOOKUP**, VLOOKUP, MATCH, CHOOSE, DATE, **DAYS**, FIND and INDEX

Based on their functionality, **450+ functions** in Excel are categorized into the following.

- Dynamic Array Functions
- Compatibility functions
- Cube functions
- Database functions
- Date and time functions
- Engineering functions
- Financial functions
- Information functions
- Logical functions
- Lookup and reference functions
- Math and trigonometry functions
- Statistical functions
- Text functions
- User-defined functions that are installed with add-ins
- Web functions