FAQ > Graphing Calculator > How do you calculate the log of any base?

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You can calculate the log of any base using the ln() function.

Examples:

  • Log (base 3) of 27 is 3. You can calculate it by typing: ln(27) / ln(3)
  • Log (base 5) of 25 is 2. Try: ln(25) / ln(5)
  • So the rule is: ln(x) / ln(base)

Last updated on December 9, 2010 by Gabor Nagy