Reliability growth workbench.
Use a declared Duane power-law model to plan additional test exposure, project cumulative MTBF, estimate a two-point growth slope, or interpret an achieved end-of-test MTBF.
Growth test time
Solve the cumulative exposure needed to move from a baseline to a target MTBF.
ProjectionDuane MTBF projection
Project cumulative and instantaneous MTBF at a future test time.
Trend estimateGrowth slope
Estimate the log-log Duane slope from two cumulative observations.
Test resultAchieved growth MTBF
Translate test time, failures, and fitted slope into end-of-test instantaneous MTBF.
Model learning, not certification.
These calculators use a deterministic power-law relationship for a repairable system under test. They do not fit a full failure-time dataset, produce confidence bounds, prove a contractual requirement, or show whether fixes are technically effective. Start with the reliability growth guide and keep the formula reference beside the test report.
A straight Duane trend assumes a stable test strategy and a meaningful sequence of corrective actions. Phase changes, delayed fixes, mixed configurations, or changed duty can invalidate a single slope.