AWS Load Balancer Cost Calculator (ALB/NLB)
Estimate load balancer cost with a simple model: fixed hourly LB fees + capacity-unit hours (LCU for ALB or NLCU for NLB). Use hours/day x days/month to normalize uptime and compare baseline vs peak traffic.
Maintained by CloudCostKit Editorial Team. Last updated: 2026-01-28. Editorial policy and methodology.
Best next steps
Use this calculator for the first estimate, then validate the answer with the closest guide or companion tool.
Inputs
Results
Model load balancers as fixed footprint plus burst capacity
Load balancer bills have a steady hourly floor and a variable usage layer. Teams often focus only on traffic and forget that idle balancers still bill, while burst traffic, bytes processed, and connection patterns can inflate the LCU or NLCU side quickly.
- Count active load balancers first so the fixed hourly baseline is visible before traffic modeling begins.
- Use average LCU or NLCU per hour from metrics, not monthly unit-hours pasted into an hourly field.
- Keep uptime, bytes, and connection behavior aligned to the same measurement window.
Where load balancer estimates usually drift
- Idle sprawl: old or rarely used balancers keep charging even when traffic is negligible.
- Burst capacity patterns: launches, incidents, and bot spikes change LCU or NLCU drivers far faster than monthly averages suggest.
- Wrong unit interpretation: confusing hourly capacity units with monthly totals can overstate or understate costs badly.
- Boundary confusion: transfer, logs, NAT, and downstream instance cost are adjacent, not part of the core balancer fee.
How to reconcile the estimate with billing data
- Compare billed LB-hours with the actual number of active balancers and their uptime.
- Check CloudWatch-derived LCU or NLCU patterns for baseline versus burst windows rather than one blended number.
- Verify that transfer or logging line items are not being mistaken for balancer usage charges.
- Run a separate peak scenario if launches or incidents create a cost shape that normal traffic does not reflect.
What to do if fixed or usage cost dominates
If fixed cost dominates, inspect balancer sprawl and consolidation opportunities. If usage dominates, isolate which LCU or NLCU driver is responsible: connections, bytes, or other capacity factors. If the full network edge bill is still higher than expected, the next review belongs with transfer, NAT, CDN, and east-west traffic rather than the load balancer alone.
Next steps
Example scenario
- 2 load balancers running 24 hours/day for 30 days, averaging 5 capacity units/hour - estimate fixed + usage components.
- Peak 220% scenario helps budget for marketing bursts.
Included
- Fixed cost from load balancers x hours/day x days/month x $/LB-hour.
- Usage cost from capacity unit-hours x $ per unit-hour (LCU/NLCU) using hours/day x days/month.
- Optional capacity unit estimator from connections, bytes, and rule evaluations.
- Optional Mbps estimator for processed GB/hour.
- Baseline vs peak scenario table for capacity spikes.
Not included
- Data transfer/egress beyond what is included in your provider's capacity unit definition.
- Downstream service costs (instances, NAT, logs, etc).
How we calculate
- Fixed cost = load balancers x (hours/day x days/month) x $ per LB-hour.
- Capacity unit-hours = avg capacity units per hour x (hours/day x days/month).
- Usage cost = capacity unit-hours x $ per capacity unit-hour.
- Total = fixed cost + usage cost.
FAQ
What should I enter as "capacity units per hour"?
Does this include cross-zone or internet egress charges?
How do I reduce load balancer cost?
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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: 2026-01-28. Reviewed against CloudCostKit methodology and current provider documentation. See the Editorial Policy .