How to use the parallel system reliability calculator
Find the reliability of two redundant components where the system works if either one works. Enter reliability of component 1, reliability of component 2 in the fields above; the system reliability (any one works), probability both fail are computed instantly and plotted on the chart so you can see how the answer changes.
Common searches this calculator answers include “parallel redundancy reliability”, “backup system reliability”, “redundant components”, “calculate parallel system reliability”, “find system reliability”.
Formula
Variables
- r1 — Reliability of component 1
- r2 — Reliability of component 2
Worked example
With reliability of component 1 = 0.9, reliability of component 2 = 0.9, the calculator gives system reliability (any one works) ≈ 99 %; probability both fail ≈ 1 %.
Frequently asked questions
What is the parallel system reliability calculator used for?
Find the reliability of two redundant components where the system works if either one works. It helps with questions such as “parallel redundancy reliability”, “backup system reliability”, “redundant components”.
What is the formula for the parallel system reliability calculation?
System reliability (any one works) (%) = 100 × (1-(1-r1) × (1-r2)). Probability both fail (%) = 100-[System reliability (any one works)]. Here r1 is reliability of component 1, r2 is reliability of component 2.
What inputs do I need for the parallel system reliability calculator?
You need reliability of component 1, reliability of component 2. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use the parallel system reliability calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the parallel system reliability result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.