Cost public IPv4 addresses now that every one bills hourly, isolate idle waste, and compare against a NAT gateway.
Since February 2024 AWS bills every public IPv4 address by the hour whether it is attached or not, which turned a free-if-attached resource into a per-address line item. That flips the economics of giving each instance its own public address: past a couple of dozen addresses, moving instances into private subnets behind a single NAT gateway is usually cheaper — until the NAT's per-GB processing charge overtakes the address savings. Idle Elastic IPs used to cost a token amount and now cost the same as attached ones, so unreleased addresses left behind by deleted stacks are pure waste that no dashboard highlights.
EC2 Elastic IP
monthly cost = price per address-hour × hours × addresses; NAT alternative = hourly price × hours + GB processed × per-GB price.
monthly cost = price per address-hour × hours × addresses; NAT alternative = hourly price × hours + GB processed × per-GB price. Since February 2024 AWS bills every public IPv4 address by the hour whether it is attached or not, which turned a free-if-attached resource into a per-address line item. That flips the economics of giving each instance its own public address: past a couple of dozen addresses, moving instances into private subnets behind a single NAT gateway is usually cheaper — until the NAT's per-GB processing charge overtakes the address savings.
Idle Elastic IPs used to cost a token amount and now cost the same as attached ones, so unreleased addresses left behind by deleted stacks are pure waste that no dashboard highlights.
This calculator takes 7 inputs: Public IPv4 addresses in use, Addresses not attached to a running resource, Price per address-hour, Hours in the billing month, NAT gateway hourly price, Data processed through a NAT gateway, NAT gateway data processing price. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Yes — AWS does not charge for IPv6 addresses. Dual-stack or IPv6-only subnets with an egress-only internet gateway sidestep both the per-address charge and NAT gateway costs, at the price of needing IPv6 support end to end.