IOPS (Input/Output Operations Per Second) measures how many read or write operations a storage device can perform each second. A single database transaction can trigger multiple I/O operations depending on index lookups, page reads, and log writes, so IOPS demand is typically higher than the raw TPS number.

How do I find my current IOPS requirements?

On Linux, use iostat -x 1 and read the r/s and w/s columns. On Windows, use Performance Monitor with the PhysicalDisk\Disk Reads/sec and Disk Writes/sec counters. On AWS RDS, check the ReadIOPS and WriteIOPS CloudWatch metrics.

What block size should I use?

Use your database page size: PostgreSQL = 8 KB, MySQL InnoDB default = 16 KB, SQL Server default = 8 KB (extent = 64 KB), Oracle default = 8 KB. For sequential log writes use 64–512 KB. Smaller blocks increase IOPS count; larger blocks increase per-I/O throughput.

What is a typical read/write ratio for OLTP databases?

Most OLTP workloads are read-heavy: 70–80% reads / 20–30% writes is common. Pure analytics/reporting skews to 95%+ reads. Write-intensive workloads (logging, event streams) can be 50/50 or higher write ratio. Check your actual metrics before provisioning.

How does latency relate to IOPS?

Latency (ms) = (Queue Depth / IOPS) × 1000. At low queue depths storage latency is close to the device raw latency (NVMe ~0.1 ms, SATA SSD ~0.1–0.5 ms, HDD 5–10 ms). As queue depth grows relative to IOPS capacity, latency rises sharply — this is the saturation point to avoid.

Does this tool send my data anywhere?

No. All calculations run in your browser with JavaScript. Nothing is sent to any server.

IOPS Calculator for Storage

Name: IOPS Calculator for Storage
Availability: InStock
Author: Nham Vu

Enter your transaction rate, read/write ratio, and block size to calculate required IOPS, throughput, and storage latency for database planning.

Workload Parameters

Transaction Rate (TPS)

Peak transactions per second for this workload

Read Ratio: 70% / Write: 30%

Slide to set the read percentage of all I/O

0% reads 50 / 50 100% reads

I/O Block Size (KB)

Match your database page size

I/Os per Transaction

Average page reads/writes triggered per transaction

Quick Examples

Enter your workload parameters and click Calculate IOPS

Read IOPS

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Write IOPS

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Total IOPS

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Storage Metrics

Aggregate Throughput —

Block Size —

I/Os per Transaction —

Transaction Rate —

Read / Write Split —

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IOPS Breakdown

Read IOPS —

Write IOPS —

IOPS / Throughput / Latency

IOPS

Block Size (KB)

Queue Depth

Outstanding I/O requests at one time (used for latency estimate)

Storage Reference

Enter IOPS and block size to calculate throughput and latency

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