Estimate a monthly Amazon RDS bill from instance hours, Multi-AZ, gp3 storage and backup storage beyond the free allowance.
RDS bills four things independently: instance-hours, the provisioned volume (not the data you put in it), backup storage above the free allowance equal to your allocated size, and data transfer. Multi-AZ is modelled as a 2× multiplier because AWS charges a separate Multi-AZ rate for both the instance and the storage, and a Reserved Instance or Compute Savings Plan discounts only the instance component. Every rate is an editable input with a realistic us-east-1 default — confirm current prices with AWS for your region, engine and licence model. Instance-hours usually dominate an RDS bill, so the two decisions that move it most — instance size and whether Multi-AZ is genuinely required for that database — are worth modelling before you launch rather than after the invoice.
RDS Cost
monthly = instances × hourly × hours × (2 if Multi-AZ) × (1 − discount) + allocated GB × GB-rate × (2 if Multi-AZ) + max(0, backup GB − allocated GB) × backup rate.
monthly = instances × hourly × hours × (2 if Multi-AZ) × (1 − discount) + allocated GB × GB-rate × (2 if Multi-AZ) + max(0, backup GB − allocated GB) × backup rate. RDS bills four things independently: instance-hours, the provisioned volume (not the data you put in it), backup storage above the free allowance equal to your allocated size, and data transfer. Multi-AZ is modelled as a 2× multiplier because AWS charges a separate Multi-AZ rate for both the instance and the storage, and a Reserved Instance or Compute Savings Plan discounts only the instance component. Every rate is an editable input with a realistic us-east-1 default — confirm current prices with AWS for your region, engine and licence model.
Instance-hours usually dominate an RDS bill, so the two decisions that move it most — instance size and whether Multi-AZ is genuinely required for that database — are worth modelling before you launch rather than after the invoice.
This calculator takes 9 inputs: Database instances, On-demand instance price, Billed hours per month, Deploy Multi-AZ, Reserved Instance or Savings Plan discount, Allocated storage per instance, Storage price, Total backup storage held, Backup storage 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.
No — they are realistic us-east-1 on-demand defaults, but AWS prices change and differ by region, engine and licence model. Replace every price field with the figure from the AWS pricing page for your region before you commit to a number.