On this webpage you find a calculator for M/G/n Loss-Systems. To calculate the blocking probability for systems with an infinite number of sources, use the Erlang-B-formula, for systems with a finite number of sources use the Engset-formula.

Remarks to the Engset-Formula. Mean gap time is the free (unoccupied) time of one source. This value can be easily derived from practical measurements and is more intuitive compared to the equivalent offer. Loss probability is the probability of lost call attempts (call congestion). In contrast to the Erlang-B formula this is different from blocking, which is the probability of a system filled with n users. For system dimensioning the loss probability offers a more accurate measure to enhance user experience for the service.

The applet needs installed and activated Java 1.4 or higher. The applet was created solely for educational purposes. Please notice, that for large offers rounding errors may occur. Precision for calculations is 32 Bit floating point. Used recursion formulas for calculation follow the ITU-D guidelines:
Handbook "Teletraffic Engineering", Study Group 2, ITU-D, Geneva 2005

In case of questions or comments please feel free to contact the institute: Contact