About Natural Log (ln)
Natural Log (ln) computes the natural logarithm of a number - the logarithm to the base e, the constant that keeps showing up in growth, decay, compound interest and calculus. Give it a number and it returns the exponent to which e must be raised to reach that number, rounded to eight decimals.
The result is written out as ln(n) equals the answer, so the sample of ten reads 2.30258509. The edges follow the maths: the logarithm of one is zero, the logarithm of e itself is one, and the logarithm of zero is negative infinity because no finite exponent reaches zero.
Two behaviours are worth knowing before you rely on an answer. Only the natural base is offered, with no base-10 or base-2 option and no reverse direction in the same tool, so an antilogarithm needs the matching tool. And out-of-domain values are printed verbatim - a negative number produces NaN and zero produces negative infinity, with no warning that the input is outside the logarithm domain.
How to use Natural Log (ln)
- 1 Enter the number you want the natural logarithm of.
- 2 Run the tool to read the answer rounded to eight decimals.
- 3 Keep inputs positive, since zero and negative numbers produce infinity and NaN.
Frequently asked questions
What base does it use?
The natural base e, around 2.718. The tool computes the natural logarithm only, with no base-10 or base-2 option.
Why did zero give negative infinity?
No finite exponent of e reaches zero, so the natural logarithm of zero is negative infinity. The tool prints that value directly rather than flagging the input.
What happens with a negative number?
It produces NaN, because the logarithm is undefined for negative inputs. There is no warning - the result simply reads NaN.
Can I compute the reverse, e to the power of a number?
Not here. The antilogarithm is a separate tool, so computing e raised to a result means switching to it.
Free, online, and private
Free to use
Natural Log (ln) is completely free. There is no account to create, no login, and no hidden charge or usage limit.
Runs online in your browser
It is a free online tool that runs entirely in your browser. Nothing to download or install — open the page and start using it right away.
Your data stays private
All processing happens locally on your device. Your input is never uploaded, stored, or tracked, so it never leaves your browser.
How Natural Log (ln) behaves in detail
These are the specifics of this implementation — the exact ranges, defaults and fixed settings you are working with.
| Parameter | Value |
|---|---|
| Input | one Number field starting at ten |
| Formula | the natural logarithm, base e, of the given number |
| Output | a single line of the form ln(n) equals the answer, rounded to eight decimals |
| Default | ln(10) reads 2.30258509 |
| Edges | ln(1) is zero, ln(0) is negative infinity, and a negative input produces NaN |
| Missing input | a missing value is read as zero, reported as ln(0) = -Infinity |
Compiled from the implementation of this tool and checked against it by itoolnet.
What Natural Log (ln) does not do
Knowing the edges of a tool saves more time than another list of its features. These are the cases where it will not do what you might expect.
- Only the natural logarithm is offered. There is no base-10 or base-2 option, and no reverse direction - the antilogarithm is a separate tool, so computing e to the power of a result means switching tools.
- Out-of-domain values are printed verbatim. Zero gives negative infinity and a negative number gives NaN, with no warning that the input is outside the domain of the logarithm.
- The answer is fixed to eight decimals with no option to change it, and a missing or non-numeric value is read as zero rather than prompting, so a blank field reports negative infinity.
Tested and documented by itoolnet, the team that builds and maintains this site.