15
$\begingroup$

All I know is that I can do log(number) to get log base ten and ln(number) to get log base e. How can I insert logarithms with other bases in Google Calculator? I can't seem to figure it out.

$\endgroup$
5
  • 8
    $\begingroup$ you can use $\log_a b = \frac{\ln b}{\ln a}$ $\endgroup$
    – Kerr
    Mar 24, 2017 at 1:17
  • 2
    $\begingroup$ @Jane That's probably as complete an answer as is possible for this question, so perhaps it's worth promoting it from a comment to an answer? $\endgroup$ Mar 24, 2017 at 1:23
  • 2
    $\begingroup$ Nice math! Good to know, but is there a more direct route? $\endgroup$ Mar 24, 2017 at 1:23
  • 3
    $\begingroup$ The Google Guide Quick Reference says that lg for $log_2$ is available in addition to log and ln, but those are the only ones. $\endgroup$
    – rogerl
    Mar 24, 2017 at 1:30
  • $\begingroup$ @Travis that's ok! at least it's helpful :) $\endgroup$
    – Kerr
    Mar 25, 2017 at 1:43

3 Answers 3

19
$\begingroup$

For base $b=10$ we can use log_10(n) or log(n)

For base $b=e$ we can use ln(n)

For base $b=2$ we can use log_2(n) or lg(n)

Other bases aren't implemented, so we use the Change of Base Rule, namely $\log_b(n) = \frac{\ln(n)}{\ln(b)}$ which we put into the calculator as ln(n)/ln(b). This works with any other base, so log(n)/log(b) would be the same.

$\endgroup$
1
$\begingroup$

Google calculator now supports arbitrary bases. For $\log_2(16)$, for example, you may now enter log2(16).

Screenshot of Google calculator

$\endgroup$
3
  • 3
    $\begingroup$ This doesn't work for arbitrary bases. log8(4) is interpreted as log(8) * 4 $\endgroup$ Oct 7, 2019 at 4:52
  • $\begingroup$ @aaron You are right. Apologies, I assumed this would work for any base; appears to only work for base 2. $\endgroup$ Oct 8, 2019 at 7:29
  • $\begingroup$ google.com/search?q=google+calculator+log243%281000 apparently only for some numbers $\endgroup$ Jan 14, 2022 at 20:16
0
$\begingroup$

You can input it into the Google search bar like this, log_base(x) would be written as:

log(x,base)

For example, log base 11 of 4 (or log_11(4) ) would look like this:

log(4,11)

As for Google calculator... not sure yet.

$\endgroup$
1
  • $\begingroup$ This is wrong. Google treats the comma as a decimal point here. You can tell because log(4,0) is equal to log(4). $\endgroup$ May 15, 2020 at 9:22

You must log in to answer this question.

Not the answer you're looking for? Browse other questions tagged .