dEdx is an online calculator for electronic stopping powers of ions in various materials. Simply select a data source, ion, target and energy and press the calculate button. You can also download our app for your android device, which works fully offline.

Get it on Google Play

Program: Ion: Target:

How to use this page

The specific energy should be formatted in either normal (12.3) or scientific notation (1.23e1).

The default input method allows you to enter one or more energies (one per line). If the requested energy is out of bounds it will not appear in the results.

In fixed energy mode, a fixed logarithmic energy grid is used starting from 1 keV/nucleon to 1 GeV/nucleon.

Finally, you can enter lower and upper bounds of an interval, and dEdx will calculate a table in either logarithmic or linear steps.

Optionally you can calculate ranges of the ions in their CSDA approximation. The CSDA range also depends on the nucleon number of your projectile, which is why it must be specified.

After the first calculation a stopping power history will appear at the bottom of the page, at default it remembers the last 5 calculations.

Energy input method

Multiple specific energies
Fixed specific energy table
User defined specific energy interval
Enter one or more specific energies below (in MeV/nucleon)

Select spacing method
Start (MeV/nucleon):

End (MeV/nucleon):

Number of points:


Calculate CSDA ranges

Specify nucleon number of projectile:

Click here to get a large graph


Specific energy (MeV/nucleon)STP (MeV cm^2/g)CSDA (g/cm^2)

Stopping power history

Elements shown


dEdx and libdEdx are developed by the Aarhus Particle Therapy Group with support from the Danish Cancer Society.

libdEdx was written by Jakob Toftegaard and Niels Bassler at the Dept. of Physics and Astronomy and Dept. of Experimental Clinical Oncology with support from Armin Lühr, Helge Knudsen and David C. Hansen.  We do not claim any correctness of the produced results, any use of these data are at own risk.

libdEdx version used on this page is: SVN-250

Please report any errors or suggestions to bassler (at)