Transit Gateway Cost Calculator

cost = attachments × hours × attachment rate + GB processed × per-GB rate; a peering mesh of the same size needs n(n − 1) ÷ 2 links. A Transit Gateway bills for every attachment for every hour it exists, plus a per-GB charge on traffic that crosses the gateway — and traffic between two attached VPCs crosses it once, not twice. The comparison worth making is against VPC peering, which has no hourly charge but needs n(n − 1) ÷ 2 connections because peering is not transitive, so the operational cost grows quadratically while the gateway grows linearly.

The crossover point between a peering mesh and a Transit Gateway hub usually sits between five and ten VPCs, and knowing where it falls for your traffic profile prevents both a premature hub and an unmanageable mesh.

This calculator takes 5 inputs: Transit Gateway attachments, Price per attachment-hour, Data processed per month, Price per GB processed, Billable 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.

The defaults are us-east-1 list prices for illustration only. Attachment and data processing rates vary by region, and cross-region peering attachments add their own transfer charge, so confirm the figures on the AWS Transit Gateway pricing page for your region.

Once. The data processing charge applies to data sent into the gateway from an attachment, so a VPC-to-VPC flow is billed a single time rather than on both the ingress and the egress attachment.