Networking costs explained: egress, transfer boundaries, NAT, and private connectivity
Most teams under-estimate networking because they model only internet egress. The reliable workflow is to list each boundary and price it separately: internet, cross-zone, cross-region, CDN origin egress, plus NAT/private endpoints.
1) List your boundaries
- Internet egress: bytes to end users or external services.
- Cross-zone: east-west traffic across zones/availability zones.
- Cross-region: replication, DR, multi-region reads.
- CDN origin egress: origin to CDN cache fill.
- NAT / private endpoints: endpoint-hours + GB processed.
2) Estimate GB/month (practical methods)
- From provider billing exports (best).
- From throughput charts (Mbps to GB/month).
- From requests/day x average response size.
3) Price each boundary separately
Provider-specific hubs
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Related calculators
Data Egress Cost Calculator
Estimate monthly egress spend from GB transferred and $/GB pricing.
API Response Size Transfer Calculator
Estimate monthly transfer from request volume and average response size.
VPC Data Transfer Cost Calculator
Estimate data transfer spend from GB/month and $/GB assumptions.
Cross-region Transfer Cost Calculator
Estimate monthly cross-region transfer cost from GB transferred and $/GB pricing.
FAQ
What counts as a networking cost?
Any traffic crossing a billing boundary: internet egress, cross-zone and cross-region transfer, NAT/private endpoints (endpoint-hours + GB processed), and sometimes load balancer traffic processed.
Why do networking bills spike?
Because these charges scale with traffic. Common spike causes are CDN cache misses (origin egress), retries during incidents, cross-zone service chatter, and image pulls/updates through NAT.
How do I estimate quickly?
Start with GB/month for each boundary (internet, cross-zone, cross-region) and price them separately. Then add NAT/private endpoints based on endpoint-hours and GB processed.
Last updated: 2026-01-22