Welcome to the efn2 Web Server

The efn2 server finds the free energy of the structure(s) contained inside a CT file. Usually, these free energies are significantly different between RNA and DNA. The default output given by this server is fairly simple, a list of free energies, lowest first. There is an option to output a detailed breakdown of these energies, as well. Note, however, that this suppresses simple output. Note also that structures which contain pseudoknots cannot be read by this server.

If you plan to leave this page while waiting for calculations to complete, please make sure you have entered a valid email address below. Leaving this page without entering a valid email address will render results inaccessible.

If you need specific help using the efn2 server, please click here.

February 14, 2018:
RNAstructure tools have been updated to version 6.0.1 which includes several improvements.
Please contact us with any questions or issues regarding this update.

Select CT Input:




Select Nucleic Acid Type:



Select efn2 Options:

If a default value is left blank, the value is treated as if it was not changed at all.



Designate Address to Email Results: