Calculate the factorial (n!) of any positive integer. Ideal for math, programming, and statistics.

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When you need to calculate permutations, combinations, probability statistics, or algorithm complexity, manually calculating the factorial of large numbers is both tedious and prone to errors. This tool can quickly and accurately calculate the factorial of any positive integer n, directly outputting the exact integer value. A factorial is a mathematical concept representing the continuous product of all positive integers from 1 to that number, denoted as n!.
Q: What is the maximum number the factorial calculator can compute?
A: Theoretically, there is no hard limit. However, due to browser performance and number representation limits, entering excessively large numbers (e.g., over 10,000) may cause the page to respond slowly or display "Infinity". We recommend entering numbers within a reasonable range based on your actual needs.
Q: What is the factorial of 0?
A: The factorial of 0 is 1. This is a mathematical definition (0! = 1) that holds significance in combinatorics and permutations of empty sets. This tool also follows this definition.
This tool only accepts positive integers (including 0). Entering negative numbers, decimals, or non-numeric characters will not yield a valid result. The calculated result is an exact integer, but for extremely large values, the browser may display it in scientific notation. This tool operates entirely on the front end; all data is processed locally in your browser, ensuring zero risk of privacy leaks.
When verifying factorial results in programming or data analysis, you can use this tool for quick cross-checking. For example, to calculate the combination C(n, k) = n! / (k! * (n-k)!), you can separately calculate the values of n!, k!, and (n-k)! before performing the final operation. Typical examples: entering 5 outputs 120 (i.e., 1×2×3×4×5); entering 10 outputs 3,628,800. For integer factorials exceeding 170, the value surpasses the representation range of double-precision floating-point numbers. The results from this tool can serve as a reliable reference for large number operations.