Add up Azure data transfer charges across internet egress, inter-region traffic, VNet peering and NAT Gateway.
Inbound data to Azure is free, so networking cost is almost entirely about what leaves and what crosses boundaries. Peering is the trap: it is metered in both directions, so a GB moved between two peered VNets is billed twice, and NAT Gateway adds both an hourly resource fee and a per-GB processing fee on top of ordinary egress. Data transfer is the line item nobody owns, and architectural choices — a private endpoint instead of peering, a service endpoint instead of NAT, or keeping chatty services in one region — change it far more than any negotiated discount; egress prices are banded by volume and region, so confirm your band in the Azure pricing calculator.
Azure Network Cost
monthly = (internet egress − 100 GB free) × egress price + inter-region GB × rate + peering GB × rate × 2 directions + NAT GB × rate + NAT hourly × 730.
monthly = (internet egress − 100 GB free) × egress price + inter-region GB × rate + peering GB × rate × 2 directions + NAT GB × rate + NAT hourly × 730. Inbound data to Azure is free, so networking cost is almost entirely about what leaves and what crosses boundaries. Peering is the trap: it is metered in both directions, so a GB moved between two peered VNets is billed twice, and NAT Gateway adds both an hourly resource fee and a per-GB processing fee on top of ordinary egress.
Data transfer is the line item nobody owns, and architectural choices — a private endpoint instead of peering, a service endpoint instead of NAT, or keeping chatty services in one region — change it far more than any negotiated discount; egress prices are banded by volume and region, so confirm your band in the Azure pricing calculator.
This calculator takes 11 inputs: Internet egress, Free egress allowance, Internet egress price per GB, Inter-region traffic, Inter-region price per GB, VNet peering traffic, Peering price per GB per direction, NAT Gateway data processed, NAT Gateway price per GB, NAT Gateway hourly rate, Billed hours per month. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.