Work out cpu credit usage instantly with clear inputs, formula shown and shareable results.
Burstable instances earn CPU credits at the baseline rate and spend them whenever utilisation exceeds it, where one credit is one vCPU-minute at 100 percent. Running above baseline is therefore only sustainable in bursts: at 45 percent against a 20 percent baseline, the instance burns credits steadily and will be throttled to baseline once the balance reaches zero.
Credit balance
earned per hour = baseline x vCPUs x 60; consumed per hour = utilisation x vCPUs x 60; hours to exhaustion = balance / net burn rate
In standard mode the instance is throttled to its baseline, which is often a fraction of nominal performance. In unlimited mode it keeps bursting and you are billed for surplus credits.
For any workload with sustained utilisation above baseline. Once you are regularly paying surplus credit charges, a fixed-performance instance is cheaper and more predictable.