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USE1-USW2-AWS-Out-Bytes - data sent between regions, and how to cut it

A usage type ending in AWS-Out-Bytes, such as USE1-USW2-AWS-Out-Bytes, is data sent from one AWS region to another; US East (N. Virginia) to US West (Oregon) is $0.02 per GB.

In your bill the usage type reads: USE1-USW2-AWS-Out-Bytes

What it costs

Charge	Price	Unit
Data transferred out to another AWS region (USE1-USW2-AWS-Out-Bytes)	$0.02	per GB

US East (N. Virginia); other regions differ. Checked 2026-11-04. Sources: AWS EC2 data transfer pricing, AWS price list file, EC2 offer, us-east-1.

Example with made-up numbers

5,000 GB per month replicated from US East to US West

5,000 GB x $0.02 = $100.00 per month on the USE1-USW2-AWS-Out-Bytes line

Replicating only the prefixes that need it (2,000 GB) = 2,000 x $0.02 = $40.00, a saving of $60.00 per month

Typical causes

S3 cross-region replication

A rule without a prefix or tag filter copies every new object.

Cross-region database replicas and backup copies

Each write and each copied backup crosses the region boundary.

A service calling another region

A caller placed in a different region from its data pays per GB on every request.

One-off migrations and bulk copies

A large copy shows as a spike that fades; check whether it is still running.

Find it in your bill

Have a CUR file queryable in Athena? Paste this and run it:

SELECT date_trunc('month', line_item_usage_start_date) AS month,
       line_item_product_code,
       line_item_usage_type,
       line_item_resource_id,
       SUM(line_item_usage_amount)  AS usage_amount,
       SUM(line_item_unblended_cost) AS cost
FROM your_cur_table
WHERE line_item_usage_type LIKE '%-AWS-Out-Bytes'
GROUP BY 1, 2, 3, 4
ORDER BY month DESC, cost DESC
LIMIT 50;

Columns used: line_item_usage_start_date, line_item_product_code, line_item_usage_type, line_item_resource_id, line_item_usage_amount, line_item_unblended_cost.

No CUR file? Use Cost Explorer

Open Billing and Cost Management, then Cost Explorer, and set the date range to the last 3 months with Monthly granularity.
Set Group by to Usage type.
In the Filters panel choose Usage type and tick the entries ending in *-AWS-Out-Bytes (the region prefix, such as USE1-, differs by region).
Read the monthly cost per usage type. A line that grows faster than your traffic is the one to chase with the fix below.
To see which resource drives it, query the CUR above; resource IDs appear only if your CUR was set up with resource IDs included, otherwise the resource column is empty.

Column names checked against: docs.aws.amazon.com/cur/latest/userguide/Lineitem-columns.html, docs.aws.amazon.com/cur/latest/userguide/cur-ate-run.html.

The fix, step by step

Verify first

Check these before you change anything: the steps below are suggestions, and only you can see your own configuration.

Find the resources behind the bytes (CUR resource id, S3 replication metrics, RDS replica list) before changing anything.
Replication and copies may be there on purpose for disaster recovery or compliance; confirm the recovery plan before removing any.
Check whether the line is one-time (a bulk copy or migration) or ongoing by looking at the daily series.
Change one flow at a time and compare the daily line for a week.

In the console

Cost Explorer > Group by Usage type, filter to the *-AWS-Out-Bytes types, to see which region pairs generate the cost.
Cost Explorer > Group by Resource (needs resource-level data) or use the CUR line_item_resource_id on these usage types to find the source.
For S3 replication: S3 > bucket > Management > Replication rules; narrow each rule with a prefix or tag filter or remove rules nobody needs.
For databases: review cross-region read replicas and backup copy rules and keep only the ones your recovery plan requires.
For services calling across regions, move the caller or a cache into the same region as its data.

With the CLI

aws ce get-cost-and-usage --time-period Start=2026-10-01,End=2026-11-01 --granularity MONTHLY --metrics UnblendedCost UsageQuantity --group-by Type=DIMENSION,Key=USAGE_TYPE --filter '{"Dimensions":{"Key":"USAGE_TYPE_GROUP","Values":["EC2: Data Transfer - Inter AZ"]}}'

aws s3api get-bucket-replication --bucket my-bucket

aws rds describe-db-instances --query "DBInstances[?ReadReplicaSourceDBInstanceIdentifier!=null].[DBInstanceIdentifier,ReadReplicaSourceDBInstanceIdentifier]"

Rollback

Re-create the replication rule or replica; data copied after the rule returns, but objects written while it was off need a batch replication job to catch up.

Find your inter-region line in your own bill

Drop in your Cost Explorer or CUR CSV. Billtrim reads it in your browser, finds the AWS-Out-Bytes lines and shows the monthly dollars.

See a sample result

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

Questions people ask

Is every region pair $0.02 per GB?

No. $0.02 per GB is the rate for US East (N. Virginia) to US West (Oregon) in the price list; other pairs have their own rates, so check the pair in your usage type.

Does this line include traffic to the internet?

No. Traffic to the internet is DataTransfer-Out-Bytes, a different line.

Part of the guide: Reduce your AWS bill as a startup: a checklist for teams with no FinOps person