Work out cpu steal time impact instantly with clear inputs, formula shown and shareable results.
Steal time is CPU the hypervisor gave to another guest while your vCPU was runnable, so it directly reduces available capacity and you pay for it regardless. Nine percent steal on eight vCPUs is effectively 7.3, and it also inflates apparent utilisation because the same work is squeezed into less real CPU time.
Steal impact
effective vCPUs = allocated x (1 - steal); wasted cost = hourly rate x steal x 730; real utilisation = demand / (1 - steal)
Below 2 to 3 percent is normal on shared instances. Sustained double-digit steal means the host is oversubscribed and you should migrate or move to dedicated capacity.
They show it once CPU credits are exhausted and the instance is throttled to its baseline, which is one of the clearest signals that the instance type is wrong.