Home » Ruby Tutorial » Ruby Programs

Ruby program to calculate the factorial of given number using recursion

Last Updated : December 15, 2025

Problem Solution

In this program, we will create a recursive function to calculate the factorial of a specified number and return the result.

Program/Source Code

The source code to calculate the factorial of a given number using recursion is given below. The given program is compiled and executed successfully.

# Ruby program to calculate the factorial 
# using the recursion

def factorial(num)
	if num == 1 
		return 1;
	else 
		return num * factorial(num-1);
	end
end

print "Enter number: ";
num = gets.chomp.to_i;  

fact = factorial(num);

print "Factorial is: ",fact;

Output

Enter number: 5
Factorial is: 120

Explanation

In the above program, we created a recursive function factorial(). Here, we read an integer number from the user and passed it to the factorial() function and got the factorial of a specified number and printed the result.

Ruby User-defined Functions Programs »