System architecture

Series System Reliability Calculator

Calculate system success probability where all three components must perform their required function during the same mission.

Component reliabilities

Enter probability values from 0 to 1 for the same mission duration.

What this calculator does

A series system succeeds only when every required component succeeds. The tool multiplies three component reliability values to show the system-level probability for the shared mission.

When to use it

Use it for a first-pass reliability block diagram where a failure in any one of the three elements prevents system function. Add only components that are actually required for the defined function.

Inputs and formula

Each R value must use the same mission time and functional success criterion. Rsystem = R1 × R2 × R3

Worked example and interpretation

0.98 × 0.96 × 0.99 produces 93.1% system reliability. The system result is lower than every component value because all three must succeed.

Practical notes and limitations

This simple model assumes independent failures. Shared power, environment, software, maintenance errors, and common utilities can create common-cause failure and make the actual system less reliable. Model those dependencies separately.