NAT Gateway & Data Transfer Calculator
Model NAT gateway hours, per-GB processing, internet egress tiers and cross-AZ chatter together — then see what VPC endpoints, an AZ-local topology, or simply deleting an idle gateway would save.
| NAT gateway hours3 x $0.045/hr x 730 hrs — charged at zero traffic | $98.55 |
| NAT data processing5,000 GB x $0.045/GB | $225.00 |
| Internet egressTiered from $0.09/GB, after 100 GB free — stacks on top of NAT processing | $171.00 |
| Cross-AZ transferBoth directions at $0.01/GB — lands in EC2-Other on your bill | $40.00 |
| Total | $534.55 |
What would actually reduce it
What this model assumes
- Internet traffic is charged twice, on purpose. Bytes leaving through a NAT gateway to the internet pay NAT processing and data transfer out. Calculators that charge one or the other understate this line by roughly half.
- Cross-AZ is billed in both directions by default, because AWS charges the sender and the receiver $0.01/GB each. This charge appears as “EC2-Other” on a bill and is routinely mistaken for compute.
- Interface VPC endpoints are not free. The endpoint saving shown above is gross — it removes NAT processing but adds the endpoint’s own hourly and per-GB charge, which we did not verify a rate for and therefore do not model. Gateway endpoints for S3 and DynamoDB genuinely are free, and that is where the saving is real.
- List prices, US East (N. Virginia). Data transfer rates vary by region and by destination; a private-pricing agreement changes the egress tiers but not the NAT rates.
- Data transfer and NAT gateway — source, read 4 Aug 2026
US East (N. Virginia) list prices, excluding any negotiated or committed-use discount. Your effective rate is lower if you have one.
Frequently asked questions
Why is my AWS NAT gateway so expensive?
Three charges stack. The gateway costs $0.045 an hour whether or not traffic flows, so three availability zones cost about $98 a month before a byte moves. Every GB through the gateway costs another $0.045 — including traffic to S3 and other AWS services, not just the internet. And internet-bound bytes pay data transfer out on top of that. Most calculators model one of the three.
How much does a NAT gateway cost per month?
A single NAT gateway costs about $32.85 a month in hourly charges alone (730 hours at $0.045). Data processing at $0.045 per GB is added on top, so a gateway handling 1 TB a month costs roughly $78, and one handling 10 TB costs roughly $483.
Do VPC endpoints save money on NAT gateway charges?
Gateway endpoints for S3 and DynamoDB are free and remove that traffic from the NAT gateway entirely — an unambiguous saving. Interface endpoints for other services carry their own hourly and per-GB charge, so they only pay off above a break-even traffic volume. This calculator shows the gross saving and says explicitly that the interface-endpoint fee is not modelled.
How much does cross-AZ data transfer cost in AWS?
One cent per GB, charged in both directions — so a GB sent from an instance in one zone to an instance in another costs two cents in total. It appears on a bill under "EC2-Other" rather than as a named line, which is why it is routinely mistaken for compute and left unexamined.
Is a NAT instance cheaper than a NAT gateway?
On paper, often yes — a small EC2 instance costs less than $32.85 a month and has no per-GB processing charge. In practice you take on patching, failover, and a single point of failure, and the instance still pays data transfer out. It is a reasonable choice for a development account and a poor one for production.
This prices one snapshot. The traffic moves every day.
Finitizer watches NAT processing, egress and cross-AZ transfer continuously across every account, attributes each charge to the workload causing it, and opens the Terraform PR for the endpoint or topology change. Read-only and keyless.