Close
This is a (DRAFT) interactive educational tool to help better understand the lognormal distribution.

The lognormal distribution is frequently used in analysis of data, and is related to the normal distribution in that the log of the distribution is normally distributed. This results in (relatively) simple formulations for the distribution, but there can be subtleties as well.

A little more information on this is in this blog post .

This visualization was put together using:
THIS TOOL IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE DEVELOPERS OF THIS TOOL OR ANY OTHER CONTRIBUTOR BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE TOOL.
B.F. Lyon, Lyon Mobile Apps, LLC
About
Lognormal Distribution with mean μL= and standard deviation σL=
$$ \cssId{equationlognormal}{\text{pdf }} f(x) = {1 \over {x \ \cssId{sigmanormal_1}{\sigma_N} \sqrt{2\pi}}} e^{- { {{ { ({ln \ x} - \cssId{meannormal_1}{\mu_N})^2 } } \over {2 \cssId{sigmanormal_2}{\sigma_N}^2} }} } $$
Underlying Normal Distribution with mean μN= and standard deviation σN=
$$ \cssId{equationnormal}{\text{pdf }} f(x) = {1 \over {\cssId{sigmanormal_3}{\sigma_N} \sqrt{2\pi}}} e^{- { {{ { (x - \cssId{meannormal_2}{\mu_N})^2 } } \over {2 \cssId{sigmanormal_4}{\sigma_N}^2} }} } $$
Mean
Median
Mode
mean
Lognormal
lognormal
Normal
normal
Reset to Default
standard deviation
Exploration of the Lognormal Distribution
Lognormal distribution with mean
Lower 95th
Upper 95th