NAT Gateway Cost Reduction Tactics

NAT Gateway is the single most expensive networking line item on the typical AWS bill that nobody planned for. The hourly fee ($0.045/hour per gateway) is rounding error. The processing fee — $0.045/GB on every byte that crosses the gateway — is catastrophic at enterprise scale. Across the engagements our advisory team audits, NAT processing averages 8-15 percent of total AWS data transfer spend, frequently hitting six figures annually for a single application.

The worst part: most of that NAT processing fee is avoidable. This guide walks through every major NAT cost reduction tactic, ranked by impact and implementation effort, with the numbers we see across $2.4B+ of reviewed AWS spend.

How NAT Gateway bills

Component	Rate	Notes
NAT Gateway hourly	$0.045 / hour	Per gateway — ~$33/month per AZ
NAT Gateway processing	$0.045 / GB	All traffic crossing the gateway
Underlying egress	$0.09 / GB first 10 TB	Additive — if destination is Internet
Underlying cross-AZ / cross-region	$0.01 / $0.02 / GB	Additive — if destination is internal

Critical fact: the processing fee applies to all bytes, regardless of destination. NAT-processed traffic to AWS services like S3, DynamoDB, ECR, and Secrets Manager pays the $0.045/GB processing fee even though the destination is inside AWS. A private-subnet EC2 instance pulling 10 TB/month of container images from ECR costs $450/month in NAT processing alone, on top of any actual egress.

The cost reduction stack

NAT cost optimization is a stack, not a single decision. The biggest wins come from combining tactics:

Tier 1: Free, mandatory — VPC Gateway Endpoints

Gateway Endpoints for S3 and DynamoDB are free, take ~5 minutes per VPC, and route traffic to those services directly instead of through NAT. Every VPC in every account should have them enabled. There is no operational complexity, no failure mode, no maintenance burden.

Typical impact: 30-50 percent reduction in NAT processing fees on environments with heavy S3/DynamoDB usage.

Tier 2: Cheap, high-impact — Interface Endpoints (PrivateLink)

For other AWS services (ECR, Secrets Manager, KMS, CloudWatch Logs, SSM, STS, EC2 API, ELB API, etc.), Interface Endpoints charge $0.01/GB processing plus $0.01/hour per AZ. Crossover math: at any sustained service-bound traffic above ~3 TB/month per VPC, PrivateLink wins.

Typical impact: another 15-30 percent reduction in NAT processing fees.

Highest-ROI services to add Interface Endpoints for:

• ECR (container image pulls)
• CloudWatch Logs (log ingestion)
• SSM (parameter store, agent communication)
• Secrets Manager
• KMS
• STS

Tier 3: Architectural — consolidate egress

If multiple VPCs each have their own NAT Gateways, you are paying separate hourly fees and missing the egress tiering benefit. Centralizing egress through a single NAT in a transit account (routed via Transit Gateway) collapses hourly fees and accumulates egress in higher discount tiers.

Typical impact: 5-15 percent additional reduction. Pairs well with Transit Gateway consolidation.

Tier 4: NAT alternatives at scale

For high-volume egress workloads, NAT alternatives become viable:

• NAT instances: A self-managed EC2 NAT instance has no processing fee — just instance cost. For very high egress volumes, this can be cheaper than NAT Gateway despite operational burden.
• Cloud-native gateway appliances: Some third-party network appliances on AWS Marketplace provide NAT without per-GB fees.
• Architectural refactor: Move egress-heavy components to public subnets with direct IP, bypassing NAT entirely.

Most enterprises don't need this tier — tiers 1-3 cover 80-95% of the savings.

Tier 5: Contract negotiation

NAT Gateway processing fees are not on the standard AWS rate card as a separate negotiable line, but they sit inside the data transfer category that is highly negotiable at EDP renewal. We routinely bundle NAT processing into a "private connectivity" line in EDP scoping.

The diagnostic process

Step-by-step to a complete NAT optimization plan:

1. Inventory NAT Gateways in every region and account. Record traffic volume per gateway.
2. Pull VPC Flow Logs on private subnets. Classify destinations: AWS services, Internet, cross-AZ AWS.
3. Quantify by destination service. Often S3, ECR, and CloudWatch Logs dominate.
4. Identify endpoint gaps. Map current Gateway Endpoint and Interface Endpoint coverage.
5. Estimate Interface Endpoint break-even for each service. Above ~3 TB/month per VPC, the math is positive.
6. Build the rollout plan starting with free Gateway Endpoints, then high-ROI Interface Endpoints, then architectural consolidation.

Case study: $214K NAT processing baseline

A media company we engaged with had $214K annualized NAT processing fees across 9 VPCs in 3 regions. Composition by destination: 41% S3, 18% ECR (image pulls), 14% CloudWatch Logs, 9% Internet egress, 7% Secrets Manager / KMS / STS, 11% miscellaneous.

The intervention:

• Enabled Gateway Endpoints for S3 and DynamoDB in all 9 VPCs. Eliminated 41% of NAT processing immediately. (Time to deploy: 2 hours.)
• Added Interface Endpoints for ECR, CloudWatch Logs, Secrets Manager, KMS, and STS in the 4 highest-volume VPCs. Eliminated another 32% of NAT processing.
• Consolidated egress for development VPCs through a transit-account NAT. Reduced hourly NAT fees and aggregated egress into higher discount tiers.
• Negotiated 28% discount on aggregate connectivity in next EDP renewal.

Net result: NAT processing fees dropped from $214K to $48K annualized — a 78 percent reduction. Pure tier-1 + tier-2 endpoint deployment delivered 73%; contract negotiation added the remaining ~5%.

Common mistakes

Five mistakes we see repeatedly:

1. "Adding endpoints is too much work." Gateway Endpoints for S3/DynamoDB are a single Terraform resource per VPC. There is no operational complexity.
2. "Interface Endpoints are expensive." Above ~3 TB/month per VPC per service, they pay back. The hourly fee is rounding error at scale.
3. "Centralized NAT is risky." With proper Transit Gateway routing and redundant NAT, centralized egress is operationally cleaner than per-VPC NAT.
4. "NAT cost is fixed." Architectural fixes routinely deliver 50-80 percent reduction; contract bundling adds more.
5. "This is too small to negotiate." If NAT is $200K+ annually, it absolutely belongs in EDP scoping.

Action checklist

1. Enable VPC Gateway Endpoints for S3 and DynamoDB in every VPC this week. (Free.)
2. Audit VPC Flow Logs and rank NAT traffic by destination service.
3. Add Interface Endpoints for any service above ~3 TB/month per VPC.
4. Evaluate egress consolidation through Transit Gateway for environments with 5+ VPCs.
5. Scope NAT processing into the connectivity bundle of your next EDP renewal.
6. Contact our advisory team for a NAT cost audit benchmarked against $2.4B+ of reviewed AWS spend.

NAT Gateway is the cheapest networking line item to fix on most AWS bills. The combination of free Gateway Endpoints, judicious Interface Endpoints, architectural consolidation, and EDP-level contract bundling routinely delivers 70-85 percent NAT cost reduction. See our complete data transfer cost guide for how NAT fits the broader transfer-cost picture.

Frequently asked questions