Rex says
Money math without the spreadsheet headache. Plug in your numbers and I'll show you exactly where the dollars land.
Try a scenario
Click to load — tweak from there.Inputs
Result
Monthly volume cost
$70.00
Capacity cost
$40.00
Extra IOPS cost
$15.00
Extra throughput cost
$15.00
Psst — share this and help Rex grow
One click, a permanent link with your numbers baked in.
How to use this
- 1Enter volume capacity (GB).
- 2Enter capacity rate ($/GB-mo).
- 3Enter provisioned iops.
- 4Enter included baseline iops.
- 5Enter iops rate above baseline ($/IOPS-mo).
- 6Enter provisioned throughput (MB/s).
- 7Enter included baseline throughput (MB/s).
- 8Read your monthly volume cost on the right — it updates as you type.
- 9Hit Share to keep the scenario or send it to someone.
About this calculator
Cloud block storage for databases is typically priced on three axes: capacity (GB), throughput (MB/s), and IOPS (input/output operations per second), and provisioned-IOPS volumes charge for IOPS separately from capacity, unlike general-purpose SSD tiers which bundle a baseline IOPS allowance into the GB price. This calculator adds up capacity cost plus any IOPS above the included baseline plus any throughput above the included baseline, which is exactly how AWS io1/io2 and gp3 volumes, and equivalent Azure/GCP premium disks, actually bill. Undersized IOPS shows up as query latency and connection pool saturation under load, and it's one of the most common causes of a database that 'suddenly' gets slow at higher traffic — the fix is usually cheaper than people expect, often $50-200/month, versus the cost of an emergency instance resize during an incident.
Worked example
Using the values the calculator loads with:
Inputs
- Volume capacity: 500 GB
- Capacity rate: 0.08 $/GB-mo
- Provisioned IOPS: 6000
- Included baseline IOPS: 3000
- IOPS rate above baseline: 0.005 $/IOPS-mo
- Provisioned throughput: 500 MB/s
- Included baseline throughput: 125 MB/s
Results
- Monthly volume cost: $70.00
- Capacity cost: $40.00
- Extra IOPS cost: $15.00
- Extra throughput cost: $15.00
What each field means
Inputs
- Volume capacity (GB)
- The volume capacity used in the calculation, measured in GB. Starts at 500 GB so you have a working example on load.
- Capacity rate ($/GB-mo)
- The capacity rate used in the calculation, measured in $/GB-mo. Starts at 0.08 $/GB-mo so you have a working example on load.
- Provisioned IOPS
- The provisioned iops used in the calculation. Starts at 6000 so you have a working example on load.
- Included baseline IOPS
- The included baseline iops used in the calculation. Starts at 3000 so you have a working example on load.
- IOPS rate above baseline ($/IOPS-mo)
- The iops rate above baseline used in the calculation, measured in $/IOPS-mo. Starts at 0.005 $/IOPS-mo so you have a working example on load.
- Provisioned throughput (MB/s)
- The provisioned throughput used in the calculation, measured in MB/s. Starts at 500 MB/s so you have a working example on load.
- Included baseline throughput (MB/s)
- The included baseline throughput used in the calculation, measured in MB/s. Starts at 125 MB/s so you have a working example on load.
Results
- Monthly volume cost
- Returned as a money amount in US dollars and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Capacity cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Extra IOPS cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Extra throughput cost
- Returned as a money amount in US dollars. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
How do I know how many IOPS my database actually needs?
Check your database's current IOPS utilization metric (CloudWatch's VolumeReadOps/VolumeWriteOps for RDS, or iostat on self-managed hosts) during peak traffic, not average. A common baseline is 3-5 IOPS per GB for general workloads and 10+ IOPS per GB for write-heavy OLTP, but the only reliable number is what you measure under real peak load.
Is gp3 or io2 cheaper for a typical production database?
gp3 includes 3,000 IOPS and 125 MB/s baseline in the per-GB price and charges modestly for anything above that, making it cheaper for most workloads under roughly 16,000 IOPS. io2 costs more per IOPS but supports far higher ceilings and better durability guarantees, so it's the right choice only once you're consistently provisioning tens of thousands of IOPS or need sub-millisecond consistency.
Does adding a read replica reduce IOPS cost on the primary?
It shifts read IOPS off the primary onto the replica's own volume, which has its own IOPS cost, so total fleet IOPS spend usually goes up, not down. The benefit is throughput and availability, not cost savings — replicas are a scaling and resilience tool, not a cost optimization, and should be justified on those terms.
Accuracy and limitations
- Results are estimates before tax, fees, and inflation unless an input explicitly covers them.
- Rates are treated as fixed for the whole period — variable-rate products will drift from this projection.
- This is educational maths, not financial advice. Check anything contractual with the lender or your accountant.
Related tools
Cloud VM Monthly Cost Calculator
Estimate the true monthly bill for a running virtual machine.
Backup Storage & Retention Cost Calculator
Project backup storage growth and cost across a retention policy.
Cloud vs Colocation TCO Calculator
Compare 3-year total cost of ownership between cloud and colocated hardware.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Database IOPS Cost Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/database-iops-cost
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/database-iops-cost" target="_blank" rel="noopener">Database IOPS Cost Calculator — RevenueLab</a> (2026).</p>
Source: [Database IOPS Cost Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/database-iops-cost) (2026).