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Reduce AWS NAT Gateway cost: six checks, in order

A NAT gateway has two meters: $0.045 per hour it exists (about $32.85 a month) and $0.045 per GB it processes. For most small teams the per-GB meter is the big one, and a large share of that traffic is often to S3 or DynamoDB, where a gateway endpoint has no additional charge. Work down this list; each step says how to prove the cause before you change anything.

US East (N. Virginia) prices checked 2026-11-04 against AWS's price list and pricing pages; other regions differ.

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The checks, in order

  1. Traffic to S3 and DynamoDB through the NAT

    $0.045 per GB; a gateway endpoint adds no charge. Check NatGateway-Bytes in Cost Explorer, then VPC Flow Logs (or CloudWatch Contributor Insights on them) on the NAT interface for a day to see the top destinations. Many to S3 prefix ranges means an endpoint will help.

    Decoder: NatGateway-Bytes: the NAT Gateway data-processing line

  2. Too many gateways

    $32.85 per gateway per month fixed. VPC console > NAT gateways: one per AZ per VPC; dev and staging VPCs rarely need the same high-availability layout as production. Check that every gateway is a route target.

    Decoder: NatGateway-Hours: the fixed monthly cost of each NAT gateway

  3. Cross-AZ hops on top of NAT bytes

    $0.01 per GB each direction between AZs. If private subnets in AZ b and c route to a NAT in AZ a, their bytes pay regional transfer as well as NAT processing. Check DataTransfer-Regional-Bytes next to NatGateway-Bytes.

    Decoder: DataTransfer-Regional-Bytes: cross-AZ traffic on your bill

  4. Image pulls and package installs

    $0.045 per GB for every pull. Compare NatGateway-Bytes spikes with deploy and autoscale times. ECR pulls from private subnets can use an ECR endpoint; check the endpoint price below first.

    Decoder: VpcEndpoint-Hours: what interface endpoints cost

  5. Logs and metrics sent to a vendor

    $0.045 per GB through the NAT, plus whatever the vendor charges. Flow-log top destinations show the vendor's address ranges. Check agent sampling and filtering settings before assuming the volume is needed.

    Decoder: NatGateway-Bytes: the NAT Gateway data-processing line

  6. Interface endpoints for AWS APIs

    $0.01 per AZ-hour plus $0.01 per GB. Only worthwhile when bytes to a given AWS service are large: 24 endpoint interfaces cost $175.20 a month before any data. Compare with the bytes you would move off the NAT at $0.045 per GB.

    Decoder: VpcEndpoint-Hours: what interface endpoints cost

Checklist

  1. Cost Explorer: Usage type NatGateway-Bytes and NatGateway-Hours, daily, last 60 days.
  2. Per gateway, CloudWatch BytesOutToDestination and BytesOutToSource show which gateway carries the bytes.
  3. Flow logs for one day on the busiest gateway (they cost money themselves: keep the window short).
  4. Create the S3 gateway endpoint on one non-production route table first; confirm the route appears and the line falls.
  5. Roll the endpoint out to the other private route tables.
  6. Only then look at consolidating gateways or adding interface endpoints.

See your NAT lines with the dollars attached

Upload a Cost Explorer or CUR CSV. Billtrim reads it in your browser, finds the NAT and transfer lines and shows what each change is worth for your numbers.

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Paste your export: how to export a Cost Explorer CSV or CUR file in two minutes.

Questions people ask

Can I just remove the NAT gateway?

Only if nothing in private subnets needs to reach the internet. Check routes and workloads first; consider whether public subnets or an egress-only design fit your security needs.

Is a NAT instance cheaper than a NAT gateway?

It avoids the per-GB processing charge but you run and patch it and pay for the instance and normal data transfer. Compare with your own traffic and who maintains it.

Does a gateway endpoint cost anything?

AWS documents no additional charge for S3 and DynamoDB gateway endpoints.

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