Excel FACT Function: A Comprehensive Guide

The FACT function in Excel calculates the factorial of a number. A factorial is the product of all positive integers less than or equal to a given positive integer. This guide will help you master the FACT function with practical examples and expert tips.

Quick Overview

• Function Category: Math & Trigonometry
• Function Version: Excel 2007 and later
• Skill Level: Intermediate
• Return Value: Number (factorial result)

Advantages of Using FACT

1. Simplifies complex factorial calculations
2. Useful in probability and statistics
3. Helps in permutation and combination problems
4. Automates mathematical computations

Syntax and Basic Usage

=FACT(number)

The number parameter must be a non-negative integer from 0 to 170. Any decimal numbers will be truncated to integers.

Example 1: Basic Factorial Calculation

=FACT(5)    // Returns 120 (5 × 4 × 3 × 2 × 1)
=FACT(0)    // Returns 1 (by definition)
=FACT(1)    // Returns 1

Real-World Applications

1. Statistical Analysis

• Calculating permutations and combinations
• Probability distributions
• Research design

2. Scientific Calculations

• Physics formulas
• Chemistry equations
• Mathematical modeling

3. Business Applications

• Quality control calculations
• Risk assessment
• Process optimization

Common Errors and Solutions

1. #NUM! Error

   • Cause: Input number is negative or greater than 170
   • Solution: Use only non-negative integers within the valid range

2. #VALUE! Error

   • Cause: Input is text or logical value
   • Solution: Ensure input is a valid number

Tips and Best Practices

1. Handle Large Numbers

   • Be aware of Excel's numerical limitations
   • Use scientific notation for large results
   • Consider using FACTDOUBLE for double factorials

2. Decimal Inputs

   • Remember that decimals are truncated
   • =FACT(5.7) is the same as =FACT(5)

3. Error Prevention

   • Validate input data before calculation
   • Use error handling functions like IFERROR

Practice Exercises

1. Basic Calculations

   • Calculate factorials of numbers 1 through 10
   • Compare results with manual calculations

2. Statistical Applications

   • Create a permutation calculator
   • Build a combination calculator

3. Advanced Usage

   • Combine FACT with other functions
   • Create a factorial table with error handling

Key Takeaways

1. FACT calculates factorials of non-negative integers
2. Maximum input value is 170
3. Useful in statistics and probability calculations
4. Decimal inputs are automatically truncated
5. Returns #NUM! for negative numbers

Next Steps

1. Practice with the provided examples
2. Explore combinations with other functions
3. Create your own factorial-based calculations
4. Join Excel communities for more learning

Need help or have questions? Feel free to ask in the comments below!