# Route contacts based on queue capacity using Amazon Connect
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To define routing decisions based on queue capacity, use a [Transfer to queue](transfer-to-queue.md) block to check whether a queue is full ([Maximum contacts in queue](set-maximum-queue-limit.md)), and then route the contact accordingly.

The [Transfer to queue](transfer-to-queue.md) block checks the [Maximum contacts in queue](set-maximum-queue-limit.md). If no limit is set, the queue is limited to the number of total concurrent contacts for the following quotas: 
+ Active tasks per instance
+ Concurrent active emails per instance
+ Concurrent calls per instance
+ Concurrent chats per instance