EBS IOPS Calculator
Check whether a volume can actually deliver the IOPS you want given the 500:1 IOPS-per-GiB ratio and the type ceiling.
About EBS IOPS Calculator
EBS caps provisioned IOPS two ways at once: a per-GiB ratio that grows with the disk and a hard per-volume ceiling that does not, so the binding limit flips as the volume grows. At 500:1 you need 200 GiB before io2 will accept 100,000 IOPS, and 512 GiB before the 256,000 ceiling becomes the limit instead. Converting IOPS to MB/s at your real average I/O size is what tells you whether the instance network or the volume runs out first. Provisioning a request the volume cannot legally accept fails at the API, and provisioning IOPS the workload cannot issue at its block size is money spent on headroom that never gets used.
Formula
EBS IOPS
achievable IOPS = min(requested, size x IOPS-per-GiB ratio, type ceiling); size needed = ceil(min(requested, ceiling) ÷ ratio).
- ratio
- Maximum provisioned IOPS per GiB, 500:1 on gp3 and io2
- ceiling
- Absolute per-volume IOPS maximum for the type
Worked example
With the default values below, EBS IOPS Calculator returns IOPS You Can Actually Provision of 75,000. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Volume sizeminimum 1 GiB
- 150 GiB
- IOPS you want to provisionminimum 0 IOPS
- 100,000 IOPS
- Maximum IOPS per GiB for the volume typeminimum 1 IOPS per GiB
- 500 IOPS per GiB
- Volume type IOPS ceilingminimum 1 IOPS
- 256,000 IOPS
- Average I/O sizeaccepts 1–1,024 KiB
- 16 KiB
Results
- IOPS You Can Actually Provision
- 75,000
- Ceiling Imposed by Volume Size
- 75,000
- Volume Size Needed for the Target
- 200 GiB
- IOPS Shortfall
- 25,000
- Implied Throughput at That I/O Size
- 1,171.9 MB/s
- Binding Constraint
- Volume size, via the IOPS-per-GiB ratio
Step by step
- 1Values used
- 2EBS IOPS
- 3IOPS You Can Actually Provision= 75,000
- 4Ceiling Imposed by Volume Size= 75,000
- 5Volume Size Needed for the Target= 200 GiB
- 6IOPS Shortfall= 25,000
- 7Implied Throughput at That I/O Size= 1,171.9 MB/s
- 8Binding Constraint= Volume size, via the IOPS-per-GiB ratio
Assumptions and limits
- The result is derived only from the 5 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 1 decimal place, 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 EBS IOPS calculated?
achievable IOPS = min(requested, size x IOPS-per-GiB ratio, type ceiling); size needed = ceil(min(requested, ceiling) ÷ ratio). EBS caps provisioned IOPS two ways at once: a per-GiB ratio that grows with the disk and a hard per-volume ceiling that does not, so the binding limit flips as the volume grows. At 500:1 you need 200 GiB before io2 will accept 100,000 IOPS, and 512 GiB before the 256,000 ceiling becomes the limit instead. Converting IOPS to MB/s at your real average I/O size is what tells you whether the instance network or the volume runs out first.
Why does EBS IOPS matter?
Provisioning a request the volume cannot legally accept fails at the API, and provisioning IOPS the workload cannot issue at its block size is money spent on headroom that never gets used.
What values do I need to enter?
This calculator takes 5 inputs: Volume size, IOPS you want to provision, Maximum IOPS per GiB for the volume type, Volume type IOPS ceiling, Average I/O size. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.
Why does my volume not hit its provisioned IOPS?
The instance is usually the limit, not the volume. Every instance type has its own EBS bandwidth and IOPS maximum, and a volume provisioned beyond that ceiling will be throttled at the instance level no matter how large it is.