What happens to accrued CPU credits when a t2.nano instance is stopped for more than seven days?

CPU Credit Persistence After Seven Days

Accrued CPU credits for a t2.nano instance are not expired or wiped simply because the instance has been stopped for more than seven days. Your existing credit balance is preserved while the instance is in a stopped state.

Technical Explanation

The burstable performance model for T2 instances separates the earning of credits from the retention of credits. While an instance is stopped, it ceases to earn new CPU credits because it is not consuming any physical host resources. However, the balance already accumulated before the stop event remains associated with the instance metadata.

Confusion regarding a "seven-day window" often stems from other AWS behaviors, such as the lifecycle of ephemeral storage or specific snapshot retention policies, but these do not apply to the CPU credit balance of burstable instances.

Verification and Management

To verify the current state of your credits after restarting a stopped instance, you can monitor the CPUCreditBalance metric. Since this is a CloudWatch metric, you can view it via the AWS CLI:

aws cloudwatch get-metric-statistics --namespace AWS/EC2 --metric-name CPUCreditBalance --dimensions Name=InstanceId,Value=YOUR_INSTANCE_ID --start-time 2026-10-14T00:00:00Z --end-time 2026-10-15T00:00:00Z --period 3600 --statistics Average

Practical Considerations

• Cost: Stopping an instance avoids compute charges, and since credits are preserved, there is no financial penalty for stopping the instance to save costs without losing your burst capacity.
• T2 Unlimited: If you have "Unlimited mode" enabled, the instance can burst beyond its accrued credits for an additional charge. This is independent of the stopped-state retention.
• Instance Store: Remember that while CPU credits are saved, any data on ephemeral instance store volumes is lost when a t2.nano is stopped.

Diagnostic Detail Needed: Are you using T2 Unlimited or Standard mode? If using Unlimited, your credit balance behaves differently during active bursts, though the retention during a stopped state remains the same.