AWS NAT Gateway Pricing: The Ultimate Cost Reduction Guide

If you’ve ever opened your AWS bill and gasped at the “EC2-Other” or “VPC” line items, you’ve likely met the NAT Gateway.

It is one of the most notoriously expensive components in the AWS ecosystem. For many data-intensive applications, the NAT Gateway bill actually exceeds the cost of the EC2 instances it serves.

In this guide, we’ll visualize exactly why it’s so expensive, explain the “Double Dip” trap, and give you 3 concrete architectural changes to slash this cost by 50-90%.

[!IMPORTANT] Calculate Your Exact Cost Don’t guess. Use our free Interactive NAT Gateway Cost Calculator to see exactly how much you’re paying based on your traffic.

Visualizing the Cost Flow

To understand the cost, you have to understand the traffic flow. Here is how a standard private subnet communicates with the internet:

graph LR
    subgraph VPC
        subgraph Private_Subnet
            EC2[EC2 Instance]
        end
        subgraph Public_Subnet
            NAT[NAT Gateway]
        end
        IGW[Internet Gateway]
    end
    Internet((Internet))

    EC2 -- "$0.01/GB (Cross-AZ)" --> NAT
    NAT -- "$0.045/GB (Processing)" --> IGW
    IGW -- "$0.09/GB (Egress)" --> Internet

The “Double Dip” Trap

AWS charges for NAT Gateways in two dimensions, but the data path often triggers three separate fees for the same packet of data.

1. The “Existence” Fee (Hourly)

You pay just for having the NAT Gateway provisioned.

• Cost: ~$0.045 per hour.
• Monthly: ~$32.85 per gateway.
• The Kicker: For High Availability (HA), you need one per Availability Zone (AZ). If you run in 3 AZs, that’s ~$100/month just for the privilege of having them exist, even with zero traffic.

2. The “Processing” Fee (Throughput)

You pay for every GB that passes through the gateway.

• Cost: ~$0.045 per GB.
• Impact: 10TB of data = $450.

3. The “Transfer” Fee (Egress)

This is the one people forget. The NAT Gateway fee covers processing, not transfer. You still pay standard Data Transfer Out rates to the internet.

• Cost: ~$0.09 per GB.

Total Cost for 1GB of Traffic: $0.01 (Cross-AZ) + $0.045 (NAT Proc) + $0.09 (Egress) = $0.145 / GB

That is a 60% markup over standard internet egress, just for using a NAT Gateway.

3 Proven Alternatives to NAT Gateways

If you want to save money, you have to stop sending data through the NAT Gateway. Here are the three best ways to do that.

Alternative 1: VPC Endpoints (Gateway Endpoints)

Savings Potential: High (100% for S3/DynamoDB) Complexity: Low

Many applications spend huge amounts of bandwidth talking to AWS services like S3 (downloading images, logs, backups) or DynamoDB.

You do not need a NAT Gateway for this. You can use a Gateway VPC Endpoint.

• Cost: Free. $0.
• How it works: It adds a route to your route table that sends S3 traffic directly to the S3 service, bypassing the NAT entirely.

Action Item: Check your VPC Route Tables immediately. If you don’t see a route to a pl-xxxx prefix (S3 prefix list), you are burning money.

Alternative 2: Public Subnets

Savings Potential: Medium Complexity: Medium

“Private Subnets for everything” is a security best practice, but it’s not a law. If you have:

• Load Balancers
• Bastion Hosts
• CI/CD Runners
• Scrapers / Crawlers

…and they are secured properly with Security Groups (allowing traffic only on specific ports), you can move them to a Public Subnet.

• Benefit: They talk directly to the Internet Gateway (IGW).
• Cost: IGW Data Processing is Free. You only pay the standard $0.09/GB egress.

Alternative 3: NAT Instances (The “Old School” Way)

Savings Potential: High Complexity: High

Before NAT Gateways existed, we used EC2 instances configured as routers (“NAT Instances”).

• Pros: You pay for the EC2 instance (cheap, can be Spot, can be t4g.nano). No data processing fee.
• Cons: You manage it. If it crashes, your private subnet loses internet. You have to handle HA scripts.
• Verdict: Only for advanced teams or non-production environments where HA isn’t critical. fck-nat is a popular open-source project that makes this easier.

Step-by-Step Cost Reduction Checklist

1. Baseline: Use our NAT Gateway Calculator to estimate your current waste.
2. Tagging: Enable “Cost Allocation Tags” in AWS Billing. Tag your NAT Gateways by environment.
3. CloudWatch: Enable BytesOutToDestination metrics. Find out who is talking.
4. VPC Endpoints: Enable S3 and DynamoDB Gateway Endpoints in all regions.
5. Architecture Review: Identify high-bandwidth workloads (e.g., image processing, big data). Can they move to public subnets? Can they use IPv6 (which is public by default)?

Summary

NAT Gateways are a convenience tax. You pay for the convenience of not managing NAT instances and not worrying about IP routing. For low-traffic apps, it’s worth it. For high-bandwidth apps, it’s a budget killer.

Stop guessing. Model your savings now: Go to Calculator →