Azure Application Gateway + WAF Cost Calculator
UK South pricing · Standard v2 / WAF v2 · Autoscale CUs · Peak vs average scenarios
call_splitGateway Configuration
speedCapacity Units
One Capacity Unit represents ~10 new connections/sec, 2,500 persistent connections, or 2.22 Mbps throughput. App Gateway autoscales between your minimum and maximum — you pay for actual CU-hours consumed.
Default 40 hrs ≈ typical business-hours pattern. Remaining 690 hrs billed at average CUs.
swap_horizData Processed
warningCommon Billing Traps
- errorAutoscale CU peak surprise
A traffic spike or DDoS event can sustain high CU for hours. At 125 CU for a full month, the CU cost alone is ~£657 on top of the base fee.
- errorStandard v2 vs WAF v2 cost delta
WAF v2 is ~1.8× Standard v2 at the same capacity. For low-traffic workloads, the base hourly fee dominates — make sure you need the managed WAF rulesets.
- errorData processing beyond 10 TB
The first 10 TB/month of data processed through the gateway is free. High-throughput workloads can tip into billed territory without realising.
- errorv1 to v2 migration billing model change
v1 gateways used fixed instance counts with predictable fees. v2 is autoscale-only — migrating from v1 to v2 introduces billing variability that surprises teams expecting a like-for-like swap.