System Reliability Calculator

Edit a Reliability Block Diagram (RBD) directly and instantly compute system availability, annual/monthly downtime, and a verifiable formula. Supports arbitrary series/parallel nesting and k-out-of-n redundancy.

Click a block to edit its parameters. Hover over a wire or above/below a block to reveal a + icon, then click to add a block in series or parallel.

System results

System availability

0.9900000000

Annual downtime

87h 36m 0s

Monthly downtime

7h 18m 0s

Formula (paste into Excel to verify)

0.99

How it's calculated