What is DFTCalc?

DFTCalc calculates the failure probability of a Dynamic Fault Tree (DFT) by making use of the compositional semantics of I/O-IMCs. In this process it docks on several state-of- the-art tools and languages: All leaves and gates of the input DFT are expressed by I/O-IMCs with the process algebra language Lotos NT; CADP is used to efficiently compose the individual I/O-IMCs; and the model checker MRMC or IMCA finally calculate the failure probability for a certain point in time. The following paragraph describes how DFTCalc aligns all these tools and formats to orchestrate the analysis of a DFT.
DFTCalc takes as input a DFT in Galileo’s textual format. This intuitive format describes a DFT top-down from its root to the basic components. Each subtree is identified by a name, logically connected with other subtrees by gates, and then refined down to the basic components. On execution, DFTCalc processes a given DFT in various stages and analyzes the system’s reliability. The tool’s output is a quantification of this attribute which is expressed as either the failure probability for a given mission time or the mean time to failure.

If you were to refer to the DFTCalc toolset in your academic paper, we would appreciate if you would use the following reference:

Fault Tree Analysis

We provide state of the art techniques for quantitative reliability analysis of your sytem. Just provide a (dynamic) fault tree and choose your options.

Reliability analysis

DFTCalc will determine the reliability of your system for a given time interval. Further, it will determine the mean-time to failure of you system.


DFTCalc provides a fully functional tool working in your browser. You can test all functionalities using our web-inerface without installing anything on your machine.


DFTCalc is provided under the MIT License. Note that the CADP tool-box, used as a backend in DFTCalc, is only free for academic use.


The DFTCAalc tool-set is used in the ArRanger project, which stands for smart railroad maintenance engineering with stochastic model checking.

Formal Methods and Tools

DFTCalc is developed in the Formal Methods and Tools (FMT) Group of the University of Twente.

Test DFTCalc now!

You are interested in DFTCalc, then go to the web-tool or download the sources.