Queue depth

Type depth and latency. 32 and 2 ms give Szac. IOPS: 16000. 1 and 1 give 1000. 64 and 0.2 give 320000. Little's law, not a fio curve.

This is (depth × 1000) / latency_ms. Not a measured QD curve. MB/s from IOPS sits on throughput (MB/s).

Input data

Additional options (optional)

Results

Enter data and click Calculate.

Throughput (MB/s from IOPS)

Opens the moved IOPS-to-MB/s card (same block-size math).

Use calculator →

Replication lag (ms)

Replication lag: a segment and hops.

Use calculator →

Throughput (MB/s)

MB/s from IOPS and the I/O block size, not a fio run.

Use calculator →

How it works

Queue depth in this calculator estimates IOPS from two numbers. 32 and 2 ms give Szac. IOPS: 16000. 1 and 1 give Szac. IOPS: 1000. 64 and 0.2 ms give Szac. IOPS: 320000. Formula: (depth × 1000) / ms. This is not fio and not disk p99.

The first field is depth. The second is latency in ms. 32 × 1000 / 2 = 16000. 1 × 1000 / 1 = 1000. 64 × 1000 / 0.2 = 320000. The KB block in the examples is 4 or 8, but the result stays IOPS.

16000 does not come from fio. 1000 is not QD=1 from NVMe. 320000 is not a p99 curve. You type depth and ms. The calculator does not read a controller queue.

Throughput next door multiplies IOPS by a block. Replication lag multiplies a segment by hops. Here 32 and 2 stay Szac. IOPS: 16000, Little's law alone.

Type 32 and 2, then Calculate. The result is Szac. IOPS: 16000. A comma in 0,2 works. Zero ms does not divide. This is not live storage.

32 and 2 give 16000. 1 and 1 give 1000. 64 and 0.2 give 320000. Another latency at 32 changes 16000.

Formula

IOPS = (depth × 1000) / latency_ms. Little's law, not a measured QD curve.

How to use

  1. Type depth 32 and latency 2.
  2. Click Calculate. The result is Szac. IOPS: 16000.
  3. 1 and 1 give 1000. 64 and 0.2 give 320000.
  4. Little's law, not a fio curve.
  5. MB/s from IOPS sits on throughput (MB/s).

32 and 2 ms = Szac. IOPS: 16000

IOPS = (depth × 1000) / ms. 32 and 2 give 16000. Little's law, not fio.

Queue
Field queue depth. 32 at 2 ms leaves 16000. Not QD from fio.
depth
The same field. 1 and 1 give 1000. 64 and 0.2 give 320000.
IOPS
The calculator primary. 32 and 2 stay Szac. IOPS: 16000. Not p99.

Examples

Example 1

  • depth 32
  • latency 2 ms
  • block 4 KB

Szac. IOPS: 16000

How many IOPS at 32 and 2 ms? Szac. IOPS: 16000. Little's law, not fio.

Example 2

  • depth 1
  • latency 1 ms
  • block 4 KB

Szac. IOPS: 1000

What about 1 and 1 ms? Szac. IOPS: 1000.

Example 3

  • depth 64
  • latency 0.2 ms
  • block 8 KB

Szac. IOPS: 320000

What about 64 and 0.2 ms? Szac. IOPS: 320000.

Common questions

How many IOPS at 32 and 2 ms?

Szac. IOPS: 16000. 32 × 1000 / 2. Little's law, not fio.

What about 1 and 1 ms?

Szac. IOPS: 1000. One command per millisecond.

What about 64 and 0.2 ms?

Szac. IOPS: 320000. 64 × 1000 / 0.2.

Is this a QD curve from fio?

No. Two typed numbers. The calculator does not read disk p99.

Why the KB block?

Optional KB block for MB/s. The result stays IOPS.

Does a comma in 0,2 work?

Yes. 64 and 0,2 give Szac. IOPS: 320000.

Is 16000 live IOPS?

No. A result from depth and ms. Not a controller.

Where do I turn IOPS into MB/s?

On throughput (MB/s). Here 16000 from 32 and 2 stays.

Does zero ms count?

No. Latency must be positive. This is not an empty queue from a test.

Knowledge sources

The calculator counts bits, bytes or throughput from your numbers. Below are SI and bit definitions (NIST).

Page updated in 2026.