RDS Cost Calculator
Estimate a monthly Amazon RDS bill from instance hours, Multi-AZ, gp3 storage and backup storage beyond the free allowance.
About RDS Cost Calculator
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.
Formula
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.
- hourly
- On-demand price of one DB instance per hour
- Multi-AZ
- Synchronous standby in a second Availability Zone
- allocated GB
- Provisioned EBS volume size, billed whether used or not
- free backup
- Backup storage equal to total allocated DB size, at no charge
Worked example
With the default values below, RDS Cost Calculator returns Estimated Monthly Cost of $983.36. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Database instancesaccepts 1–200 instances
- 2 instances
- On-demand instance priceminimum 0 $/hour
- 0.258 $/hour
- Billed hours per monthaccepts 0–744 hours
- 730 hours
- Deploy Multi-AZ
- Yes
- Reserved Instance or Savings Plan discountaccepts 0–75 %
- 0 %
- Allocated storage per instanceaccepts 20–65,536 GB
- 500 GB
- Storage priceminimum 0 $/GB-month
- 0.115 $/GB-month
- Total backup storage heldaccepts 0–500,000 GB
- 750 GB
- Backup storage priceminimum 0 $/GB-month
- 0.095 $/GB-month
Results
- Estimated Monthly Cost
- $983.36
- Instance Hours
- $753.36
- Allocated Storage
- $230.00
- Backup Storage
- $0.00
- Billable Backup StorageBackup storage is free up to the total allocated size of your databases.
- 0 GB
- Estimated Annual Cost
- $11,800.32
Step by step
- 1Values used
- 2RDS Cost
- 3Estimated Monthly Cost= 983.36
- 4Instance Hours= 753.36
- 5Allocated Storage= 230.00
- 6Backup Storage= 0.00
- 7Billable Backup Storage= 0 GB
- 8Estimated Annual Cost= 11,800.32
Assumptions and limits
- The result is derived only from the 9 inputs listed above. Anything not among them is not part of the calculation.
- In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
- Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is RDS Cost calculated?
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.
Why does RDS Cost matter?
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.
What values do I need to enter?
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.
Are these prices current?
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.