AWS ALB LCU / NLB NLCU Calculator

Estimate average ALB LCU (or NLB NLCU) from the common billing drivers: new connections, active connections, bytes processed, and (for ALB) rule evaluations. Compare baseline vs peak driver rates.

Inputs

LB type
New connections / sec
~2,400 new connections/min.
Active connections (avg)
Processed GB / hour
Avg 1.78 Mbps.
Rule evals / sec (ALB)
Scenario presets
Use averages for budgeting; model peaks separately. This uses the common LCU/NLCU driver definitions; verify your provider docs and region pricing.

Results

Estimated capacity units (avg per hour)
1.6
Driver: new connections
1.6
Driver: active connections
0.667
Driver: processed bytes
0.8
Driver: rule evaluations
0.3

How to get your inputs

  • Inputs: use billing exports, metrics, or logs to get real counts/GB where possible.
  • Units: convert throughput (Mbps) or rates (RPS) into monthly units when needed.
  • Scenarios: build a baseline and a high-usage scenario to avoid under-budgeting.

Result interpretation

  • LCU/NLCU is the max driver; focus on the largest driver first.
  • Processed bytes often dominates during large payload spikes.

Common mistakes

  • Using a single average and ignoring peak/incident scenarios.
  • Double-counting or missing adjacent line items (transfer, logs, retries).

Scenario planning

Scenario Connections Processed GB/hr Rule evals
Baseline Expected Expected Expected
Peak High High Burst

Validate after changes

  • Compare your estimate to the first real bill and adjust assumptions.
  • Track the primary driver metric (requests/GB/count) over time.

Next steps

Guides All calculators Load balancer cost calculator Guide: LCU/NLCU explained Guide: load balancer cost Guide: ALB vs NLB cost
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Example scenario

  • If you have 40 new connections/sec, 2,000 active connections, and 0.8 GB/hour processed -> estimate average LCU/NLCU.
  • Use this to convert metrics into "capacity units per hour" for the load balancer cost calculator.
  • Peak 230% scenario highlights the max-driver jump during traffic spikes.

Included

  • LCU/NLCU units estimate from inputs (drivers).
  • Shows which driver dominates (max of drivers).
  • Baseline vs peak scenario table for driver spikes.

Not included

  • Actual pricing (use the load balancer cost calculator after you estimate units/hour).
  • Provider-specific exceptions, rounding rules, and tiering unless you reflect them elsewhere.

How we calculate

  • Compute each driver's units as (measured value / driver threshold).
  • Capacity units per hour = max(driver units).
  • Use the result as "capacity units (avg per hour)" for a monthly cost estimate.

FAQ

Why does this take the max of drivers?
LCU/NLCU billing is commonly based on the maximum of several usage dimensions (connections, bytes processed, and for ALB, rule evaluations).
Where do I get these inputs?
Use load balancer metrics for new connections, active connections, and bytes processed. If you don't have rule evaluation metrics, approximate from request rate and routing rules.
How do I turn LCU/NLCU into dollars?
Plug "capacity units (avg per hour)" into the load balancer cost calculator along with your $/unit-hour pricing.

Related tools

Load balancer cost calculator Guide: LCU/NLCU explained Guide: load balancer cost Guide: ALB vs NLB cost Guide: estimate LCU from metrics

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Disclaimer

Educational use only. Not legal, financial, or professional advice. Results are estimates based on the inputs and assumptions shown on this page. Verify pricing and limits with your providers and documentation.

Last updated: 2026-01-29