Price a Cloud SQL instance from per-vCPU and per-GB rates, then add high availability, read replicas and backups.
Cloud SQL bills vCPU and memory separately, then multiplies the compute and data-storage lines by two when regional HA is enabled because the standby is a full second copy. Read replicas are billed as their own instances, and committed use discounts apply only to the compute meter — never to storage or backups. HA plus two read replicas quietly turns one instance into four billable machines, so the topology decision dominates the size decision. Check the current per-vCPU, per-GB and storage rates for your edition and region in the Google Cloud pricing calculator before you size a fleet.
Cloud SQL Cost
monthly = (vCPU × vCPU rate + GB × GB rate) × hours × HA factor × (1 − commitment discount) + storage GB × storage price × HA factor + replicas × (compute + storage) + backup GB × backup price.
monthly = (vCPU × vCPU rate + GB × GB rate) × hours × HA factor × (1 − commitment discount) + storage GB × storage price × HA factor + replicas × (compute + storage) + backup GB × backup price. Cloud SQL bills vCPU and memory separately, then multiplies the compute and data-storage lines by two when regional HA is enabled because the standby is a full second copy. Read replicas are billed as their own instances, and committed use discounts apply only to the compute meter — never to storage or backups.
HA plus two read replicas quietly turns one instance into four billable machines, so the topology decision dominates the size decision. Check the current per-vCPU, per-GB and storage rates for your edition and region in the Google Cloud pricing calculator before you size a fleet.
This calculator takes 14 inputs: vCPUs, Memory, Price per vCPU-hour, Price per GB-hour, Hours in the billing month, Data storage, SSD storage price per GB, Backup storage retained, Backup price per GB, Enable regional high availability, Read replicas, Commitment term, 1-year commitment discount, 3-year commitment discount. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Only if it serves traffic you cannot lose. A replica is already a separate copy in its own zone, so most designs run replicas as zonal instances and reserve regional HA for the primary, which halves the replica bill.