Skip to content
Calcrivo

EC2 EBS Bandwidth Calculator

Find whether volume throughput, volume IOPS or the instance EBS-optimised limit caps your storage performance.

Inputs

MB/s

From the instance type's EBS-optimised row — 4750 Mbps is about 593 MB/s.

IOPS
volumes
MB/s

gp3 starts at 125 MB/s and can be raised to 1000 MB/s.

IOPS
KB

EBS meters IOPS in up to 256 KB units, so small blocks burn IOPS and large blocks burn throughput.

Achievable Throughput

188MB/s

Achievable IOPS

12,000

Aggregate Volume Throughput

1,000MB/s

Throughput Implied by the IOPS Limit

188MB/s

Unused Instance Bandwidth

406MB/s

Binding Limit

Volume IOPS at this block size

Step by step

  1. Values used

    Instance EBS bandwidth limit = 593 MB/s; Instance EBS IOPS limit = 18,750 IOPS; Volumes attached = 4 volumes; Throughput provisioned per volume = 250 MB/s; IOPS provisioned per volume = 3,000 IOPS; Average I/O block size = 16 KB

  2. EC2 EBS Bandwidth

    achievable MB/s = min(volumes × volume MB/s, volumes × volume IOPS × block size, instance EBS bandwidth).

  3. Achievable Throughput

    = 188 MB/s

  4. Achievable IOPS

    = 12,000

  5. Aggregate Volume Throughput

    = 1,000 MB/s

  6. Throughput Implied by the IOPS Limit

    = 188 MB/s

  7. Unused Instance Bandwidth

    = 406 MB/s

  8. Binding Limit

    = Volume IOPS at this block size

How it works

Storage performance is the minimum of three independent ceilings: what the volumes can deliver in MB/s, what their IOPS budget delivers once you multiply by the average block size, and what the instance's EBS-optimised channel allows in total. Block size is the hinge — at 4 KB the IOPS limit binds long before throughput, while at 256 KB or more the throughput limit binds first. Adding volumes or provisioning more IOPS does nothing once the instance EBS-optimised limit is the binding constraint, so identifying which of the three ceilings is active tells you whether to change the volume or the instance.

Formula

EC2 EBS Bandwidth

achievable MB/s = min(volumes × volume MB/s, volumes × volume IOPS × block size, instance EBS bandwidth).

block size
Average I/O size in MB, used to convert IOPS to MB/s
aggregate
Sum across all attached volumes
instance limit
EBS-optimised ceiling shared by every volume on the instance

Frequently Asked Questions

How is EC2 EBS Bandwidth calculated?

achievable MB/s = min(volumes × volume MB/s, volumes × volume IOPS × block size, instance EBS bandwidth). Storage performance is the minimum of three independent ceilings: what the volumes can deliver in MB/s, what their IOPS budget delivers once you multiply by the average block size, and what the instance's EBS-optimised channel allows in total. Block size is the hinge — at 4 KB the IOPS limit binds long before throughput, while at 256 KB or more the throughput limit binds first.

Why does EC2 EBS Bandwidth matter?

Adding volumes or provisioning more IOPS does nothing once the instance EBS-optimised limit is the binding constraint, so identifying which of the three ceilings is active tells you whether to change the volume or the instance.

What values do I need to enter?

This calculator takes 6 inputs: Instance EBS bandwidth limit, Instance EBS IOPS limit, Volumes attached, Throughput provisioned per volume, IOPS provisioned per volume, Average I/O block 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 16 KB workload not hit the volume's rated MB/s?

Because the IOPS budget caps you first. Four gp3 volumes at 3000 IOPS give 12,000 IOPS, which at 16 KB is only about 188 MB/s regardless of the 250 MB/s each volume is rated for. Larger I/O sizes, or more provisioned IOPS, are the only ways up.

You might also need

Related Calculators

EC2 Network Throughput CalculatorEC2 Storage Requirement CalculatorEC2 Boot Time Calculator