PyroSim Downloads

Free Trial

Register for a 30-day full access Free Trial license. An active license is required in order to access the software. All work completed during the evaluation will remain available upon license purchase.


Current Version Download Link
PyroSim 2020 64-bit (FDS 6.7.4) PyroSim-2020-3-0729-x64-en.msi
PyroSim Release Notes

To request a download link for another version of PyroSim, please contact

License Activation

To activate your copy of PyroSim:

  1. Start PyroSim
  2. In the Licensing and Activation dialog, select Online Activation
  3. In the Key box, type the activation key from your purchase receipt or Free Trial email
  4. Click Activate

The information at the bottom of the Licensing and Activation dialog should be updated to show your new license information. If you receive an error message or are otherwise unable to use the online activation feature, please email with the ‘Computer Information’ shown in the dialog to receive a license file.

Floating Licenses

To use floating licenses, please follow the instructions in the Floating License Manager User Manual. You will need to install and license the Thunderhead License Manager, then Pathfinder can be installed on each workstation and configured to use the floating license server.

Version Download Link
Floating License Manager ThunderheadLM-2020-1-0402.msi

Virtual Machine Use

Running the license server on a Virtual Machine (VM) is blocked by default. You will need to send a request to email to for this feature to be enabled.

Cluster Simulations

For PyroSim 2015.3 and more recent, you will install PyroSim on every node you want to use in the cluster. You do not need to activate the software on these computers if you do not intend to run the PyroSim program on them. The installation alone will setup the computer to be available for cluster simulations.