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Azure Disk IOPS Calculator

Find the real IOPS and throughput of an Azure disk layout after P-series limits, striping and the VM cap are applied.

About Azure Disk IOPS Calculator

On Premium SSD you cannot buy IOPS directly — performance is a fixed property of the snapped disk size, so a P30 gives 5,000 IOPS whether you need 500 or 50,000. Striping multiple disks multiplies the disk-side limit, but the VM's own uncached IOPS and throughput caps sit in front of it, and the smaller of the two is what the application sees. Most 'slow disk' tickets in Azure are actually VM-level caps, and adding a bigger disk to a small VM changes nothing; Premium SSD v2 and Ultra let you provision IOPS independently of size, which is often cheaper than buying capacity you do not need.

Formula

Azure Disk IOPS

Premium SSD IOPS and MB/s are fixed by the snapped P-series size; striped disks add up, then the VM's uncached limits cap the total: effective = min(disks × per-disk limit, VM limit).

per-disk limit
IOPS or MB/s that the P-series size grants, or the value you provision on v2 and Ultra
VM limit
Uncached IOPS and throughput ceiling of the VM size
burst
Credit-funded 3,500 IOPS ceiling available on P30 and smaller disks

Worked example

With the default values below, Azure Disk IOPS Calculator returns Effective IOPS of 10,000. Change any input above and every figure here is recalculated in your browser.

Inputs used

Size of each diskaccepts 4–65,536 GiB
1,024 GiB
Disks striped togetheraccepts 1–64 disks
2 disks
Disk tierone of Premium SSD (fixed per size), Premium SSD v2 (provisioned), Ultra Disk (provisioned)
Premium SSD (fixed per size)
Provisioned IOPS per disk (v2 / Ultra)accepts 100–400,000 IOPS
8,000 IOPS
Provisioned throughput per disk (v2 / Ultra)accepts 1–10,000 MB/s
300 MB/s
VM uncached IOPS limitaccepts 100–900,000 IOPS
12,800 IOPS
VM uncached throughput limitaccepts 1–20,000 MB/s
600 MB/s

Results

Effective IOPS
10,000 IOPS
IOPS per Disk
5,000 IOPS
Aggregate Disk IOPS
10,000 IOPS
Effective Throughput
400 MB/s
On-demand Burst IOPS
5,000 IOPS
Limiting Factor
Disk provisioning — the VM still has headroom

Step by step

  1. 1Values used
  2. 2Azure Disk IOPS
  3. 3Effective IOPS= 10,000 IOPS
  4. 4IOPS per Disk= 5,000 IOPS
  5. 5Aggregate Disk IOPS= 10,000 IOPS
  6. 6Effective Throughput= 400 MB/s
  7. 7On-demand Burst IOPS= 5,000 IOPS
  8. 8Limiting Factor= Disk provisioning — the VM still has headroom

Assumptions and limits

  • The result is derived only from the 7 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 whole numbers, 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 Azure Disk IOPS calculated?

Premium SSD IOPS and MB/s are fixed by the snapped P-series size; striped disks add up, then the VM's uncached limits cap the total: effective = min(disks × per-disk limit, VM limit). On Premium SSD you cannot buy IOPS directly — performance is a fixed property of the snapped disk size, so a P30 gives 5,000 IOPS whether you need 500 or 50,000. Striping multiple disks multiplies the disk-side limit, but the VM's own uncached IOPS and throughput caps sit in front of it, and the smaller of the two is what the application sees.

Why does Azure Disk IOPS matter?

Most 'slow disk' tickets in Azure are actually VM-level caps, and adding a bigger disk to a small VM changes nothing; Premium SSD v2 and Ultra let you provision IOPS independently of size, which is often cheaper than buying capacity you do not need.

What values do I need to enter?

This calculator takes 7 inputs: Size of each disk, Disks striped together, Disk tier, Provisioned IOPS per disk (v2 / Ultra), Provisioned throughput per disk (v2 / Ultra), VM uncached IOPS limit, VM uncached throughput limit. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.

Related Calculators

Azure Disk IOPS Calculator | Calcrivo