Unlimited mode for burstable performance instances

A burstable performance instance configured as unlimited can sustain high CPU utilization for any period of time whenever required. The hourly instance price automatically covers all CPU usage spikes if the average CPU utilization of the instance is at or below the baseline over a rolling 24-hour period or the instance lifetime, whichever is shorter.

For the vast majority of general-purpose workloads, instances configured as unlimited provide ample performance without any additional charges. If the instance runs at higher CPU utilization for a prolonged period, it can do so for a flat additional rate per vCPU-hour. For information about pricing, see Amazon EC2 pricing.

T4g, T3a, and T3 instances launch as unlimited by default (unless you change the default). If the average CPU usage over a 24-hour period exceeds the baseline, you incur charges for surplus credits. For more information, see Surplus credits can incur charges.