# Managed NAT Gateway with excessive data transfer Canonical: https://www.pointfive.co/efficiency-hub/inefficiencies/managed-nat-gateway-with-excessive-data-transfer NAT Gateways are convenient for enabling outbound access from private subnets, but in data-intensive environments, they can quietly become a major cost... By: Taylor Houck [Cloud Efficiency Hub](https://www.pointfive.co/efficiency-hub) # Managed NAT Gateway with Excessive Data Transfer The short version NAT Gateways are convenient for enabling outbound access from private subnets, but in data-intensive environments, they can quietly become a major cost driver. [Taylor Houck](https://www.linkedin.com/in/twhouck/) Cloud FinOps Specialist @ PointFive AWS service [AWS NAT Gateway](https://www.pointfive.co/efficiency-hub/cloud-services/aws-nat-gateway) Category [Networking](https://www.pointfive.co/efficiency-hub/service-category/networking) Reference CER-0075 Type Inefficient Architecture ## Explanation Why the waste happens and who it affects. When large volumes of traffic flow through the gateway - particularly during batch processing, frequent software updates, or hybrid cloud integrations - the per-GB charges accumulate rapidly. In some cases, replacing a managed NAT Gateway with a self-managed NAT instance can substantially reduce costs, provided that the organization is prepared to operate and maintain the alternative solution. ## Billing model The pricing dimensions that drive this cost. NAT Gateway pricing includes: - Hourly cost per deployed gateway per Availability Zone - Per-GB data processing fees for all traffic routed through the gateway These charges apply regardless of usage pattern and can scale significantly in high-throughput environments. ## How to detect 6 checks to find it in your estate. - Identify NAT Gateways with consistently high data processing volumes over the lookback period - Review per-GB transfer charges to assess whether NAT Gateway usage represents a significant portion of total networking costs - Determine whether traffic patterns are driven by expected workload behavior or architectural inefficiencies - Evaluate whether alternative designs - such as VPC endpoints or NAT instances-could reduce data processing costs - Consider that replacing a managed NAT Gateway with a self-managed NAT instance introduces operational overhead (e.g., scaling, patching, monitoring). - Confirm whether the potential savings outweigh the additional management effort ## How to fix How to remove the waste. In environments with large volumes of outbound traffic, consider replacing the managed NAT Gateway with a self-managed NAT instance to reduce per-GB data processing costs. Alternatively, evaluate architectural changes to reduce or avoid NAT usage altogether - such as using VPC endpoints for AWS service access. Weigh the trade-offs between cost savings and the operational complexity of managing your own NAT infrastructure. ## Documentation Vendor references for pricing and configuration. - [AWS NAT Gateway Pricing aws.amazon.com](https://aws.amazon.com/vpc/pricing/#nat_gateway) - [NAT Gateway vs. NAT Instance Comparison docs.aws.amazon.com](https://docs.aws.amazon.com/vpc/latest/userguide/vpc-nat-comparison.html) ## Related inefficiencies [Browse the library](https://www.pointfive.co/efficiency-hub) - AWS NAT Gateway CER-0325 ### [Excessive NAT Gateway Data Processing Charges from Unoptimized Traffic Routing](https://www.pointfive.co/efficiency-hub/inefficiencies/excessive-nat-gateway-data-processing-charges-from-unoptimized-traffic-routing) NAT Gateway charges a per-gigabyte data processing fee on all traffic that passes through it - in either direction - regardless of whether the destination is the public internet or another AWS service in the same region. This per-GB charge... Networking - AWS NAT Gateway CER-0128 ### [Suboptimal Cross-AZ Routing to NAT Gateway](https://www.pointfive.co/efficiency-hub/inefficiencies/suboptimal-cross-az-routing-to-nat-gateway) NAT Gateways are designed to serve private subnets within the same Availability Zone. When subnets in one AZ are configured to route traffic through a NAT Gateway in a different AZ, the traffic crosses AZ boundaries and incurs inter-AZ... Networking - AWS NAT Gateway CER-0106 ### [Suboptimal Routing Through NAT Gateway Instead of VPC Endpoint](https://www.pointfive.co/efficiency-hub/inefficiencies/suboptimal-routing-through-nat-gateway-instead-of-vpc-endpoint) Workloads in private subnets often access AWS services like S3 or DynamoDB. If this traffic is routed through a NAT Gateway, it incurs both hourly and data processing charges. However, AWS offers VPC Gateway Endpoints (for S3/DynamoDB) and... Networking --- Source: the public page above. Product screenshots and illustrative interfaces are examples, not live customer data.