How does Cloud SQL high availability work?

Cloud SQL HA creates a standby instance in a different zone within the same region. The standby uses synchronous replication and automatic failover. Enabling HA roughly doubles the compute cost since you run two instances. The estimator shows the exact cost increase so you can weigh reliability against budget.

What are Committed Use Discounts for Cloud SQL?

CUDs provide up to 25% discount for 1-year commitments and 52% for 3-year commitments on Cloud SQL vCPU and memory costs. Unlike Reserved Instances on other providers, CUDs apply at the project level and can cover any Cloud SQL instance. The estimator calculates your savings for each term length.

Does the estimator include network egress costs?

Yes. The estimator includes charges for data egress between the Cloud SQL instance and clients in different regions or on the internet. Intra-region traffic to Compute Engine VMs is free. Cross-region and internet egress rates are broken out separately.

Cloud SQL Cost Estimator

StorageGCP

Estimate Cloud SQL costs for MySQL, PostgreSQL, and SQL Server with HA, read replicas, and Committed Use Discounts.

Last verified: May 2026

Cloud SQL Configuration

Example Presets

Database Engine

Machine Type

High Availability (HA)

Doubles instance cost by adding a standby in another zone

Read Replicas

Each replica costs the same as the primary instance.

Storage & Backups

Storage Type

Storage (GB)

Backup Storage (GB)

$0.080/GB-month

Network Egress (GB)

$0.12/GB cross-region

Committed Use Discount (CUD)

CUD discounts apply to compute (instance) costs only, not storage or licenses.

Raw Output

Output will appear here...

About This Tool

The Cloud SQL Cost Estimator calculates monthly costs for Google Cloud SQL instances running MySQL, PostgreSQL, or SQL Server. It covers machine type selection (shared-core to high-memory), storage type (SSD or HDD), high availability with regional failover, read replica pricing, and backup storage. The tool also models Committed Use Discounts that can reduce compute costs by up to 25% for 1-year commitments and 52% for 3-year commitments. Enter your desired configuration to see a detailed cost breakdown that separates compute, storage, networking, and backup charges for accurate budget planning.

Real-World Scenario

Your team's primary PostgreSQL on Cloud SQL is a db-custom-8-32 with HA + 1 TB SSD, costing $1,400/month. The CFO asks for cost reduction. The estimator shows: 1-year CUDs save 25% on compute = $230/month. Switching daily-backup retention from 30 to 14 days saves $40/month. Adding a replica for reads (currently going to primary) costs +$700/month — but lets you size down the primary to db-custom-4-16, saving $340/month. Net effect: $1,400 → $1,490 with 2x read throughput AND 25% compute discount. Total cost-per-query drops 50%.

When to Use This Tool

•Estimating the monthly cost of a high-availability Cloud SQL PostgreSQL instance with two read replicas for a production web application.
•Comparing SSD versus HDD storage costs for a Cloud SQL MySQL instance where high IOPS are not required.
•Calculating Committed Use Discount savings for a Cloud SQL deployment that will run continuously for at least one year.
•Sizing a Cloud SQL for SQL Server instance and comparing licensing costs against Azure SQL Database.

Pro Tips

TIP

Cloud SQL Enterprise Plus edition (announced 2023, GA 2024) offers up to 3x the read throughput and near-zero downtime maintenance vs. standard Enterprise edition for ~50% more cost. For high-traffic production OLTP, the throughput improvement often pays for itself in not needing additional read replicas.

TIP

Cloud SQL HA fails over within ~60 seconds in 99% of cases, but the failover process closes all open connections. Applications without connection pooling that handles reconnection will see errors during failover. Always test failover with realistic traffic before relying on it for SLAs.

TIP

Cloud SQL backups are billed at $0.08/GB/month — the same rate as the database storage. Default 7-day retention on a 1 TB database adds ~$80/month invisibly. For long-retention backups (30+ days), consider exporting to Cloud Storage Coldline at $0.004/GB/month (20x cheaper) for compliance archives.

How It Works Under the Hood

The estimator computes Cloud SQL cost across components: machine type vCPU and memory hourly rates × hours (HA roughly doubles), storage type SSD/HDD GB × per-GB-month rate, backup storage based on retention × per-GB-month rate, and read replica costs (each replica is a separate billable instance at the same compute rate). Committed Use Discounts apply to vCPU and memory portions when 1-year or 3-year terms are selected.

Frequently Asked Questions

How does Cloud SQL high availability work?: Cloud SQL HA creates a standby instance in a different zone within the same region. The standby uses synchronous replication and automatic failover. Enabling HA roughly doubles the compute cost since you run two instances. The estimator shows the exact cost increase so you can weigh reliability against budget.
What are Committed Use Discounts for Cloud SQL?: CUDs provide up to 25% discount for 1-year commitments and 52% for 3-year commitments on Cloud SQL vCPU and memory costs. Unlike Reserved Instances on other providers, CUDs apply at the project level and can cover any Cloud SQL instance. The estimator calculates your savings for each term length.
Does the estimator include network egress costs?: Yes. The estimator includes charges for data egress between the Cloud SQL instance and clients in different regions or on the internet. Intra-region traffic to Compute Engine VMs is free. Cross-region and internet egress rates are broken out separately.

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