How AWS ALB Pricing Works
An Application Load Balancer bills two components every month: a flat hourly charge per ALB, plus Load Balancer Capacity Units (LCUs). AWS measures four dimensions each hour - new connections per second, active connections, processed bytes (bandwidth), and rule evaluations per second - converts each to an LCU count, and bills you for whichever dimension is highest that hour, not the sum of all four.
The Four LCU Dimensions
One LCU covers: 25 new connections/sec, 3,000 active connections, 1 MB/sec of processed bytes, or 1,000 rule evaluations/sec. A traffic pattern with many short-lived connections and simple routing rules is usually driven by the New Connections dimension; a traffic pattern with large payloads or many host/path-based rules is usually driven by Bandwidth or Rule Evaluations instead.
Why Use This Calculator?
Knowing which LCU dimension actually drives your bill tells you where optimization pays off - and where it doesn't. Reducing listener rules does nothing to your cost if bandwidth is the driver; enabling keep-alive to cut active connections does nothing if rule evaluations are the bottleneck. This calculator computes all four dimensions from your traffic shape and highlights the one AWS is actually charging you for.