# How big are factorials?

DevFeed: [How big are factorials?](<https://devfeed.tech/articles/how-big-are-factorials-35142.md>)

Original publisher: [Read original article](<https://eli.thegreenplace.net/2026/how-big-are-factorials/>)

Author: Eli Bendersky

Published: 2026-08-28T01:52:00Z

Content type: tutorial

Language: en

Sources: [Eli Bendersky](<https://devfeed.tech/sources/eli-bendersky.md>)

Topics: [math](<https://devfeed.tech/topics/math.md>), [function](<https://devfeed.tech/topics/function.md>)

Tags: [function](<https://devfeed.tech/tags/function.md>), [gamma](<https://devfeed.tech/tags/gamma.md>), [math](<https://devfeed.tech/tags/math.md>), [misc](<https://devfeed.tech/tags/misc.md>), [number](<https://devfeed.tech/tags/number.md>)

## AI overview

This tutorial explains how to estimate the number of digits in factorials, using 52! as an example. It introduces the Gamma function and outlines Stirling's approximation and its derivation using Laplace's method.

## Source excerpt

The other day, I found myself wondering how big 52! (52 factorial) is, and that led me to ponder how these could be estimated without a calculator or a computer. It turns out there's some fairly interesting math behind being able to estimate the size (number of digits) of ...