Message Queue Size Calculator
Size a message queue from arrival rate, retention and message size.
About Message Queue Size Calculator
Queue storage multiplies by the replication factor, so a three-times replicated topic needs three times the raw volume. Retention is usually the largest and most adjustable term. Log-based brokers retain messages after consumption to allow replay, which makes retention a storage decision rather than a delivery one.
Formula
Message Queue Size
Storage = rate × retention seconds × compressed message size × replication factor
- replication factor
- Copies kept for durability, each consuming full storage
- retention
- How long messages remain readable after consumption
Worked example
With the default values below, Message Queue Size Calculator returns Storage Required of 4,055.500. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Messages per secondminimum 0
- 5,000
- Average message sizeminimum 0 bytes
- 1,200 bytes
- Retention periodminimum 0 hours
- 168 hours
- Replication factoraccepts 1–10
- 3
- Compression savingaccepts 0–100 %
- 60 %
Results
- Storage Required
- 4,055.500 GB
- Ingress Rate
- 5.7220 MB/s
- Storage Before Replication
- 1,351.833 GB
- Daily Volume
- 193.119 GB
- Messages Retained
- 3,024,000,000
Step by step
- 1Values used
- 2Message Queue Size
- 3Storage Required= 4,055.500 GB
- 4Ingress Rate= 5.7220 MB/s
- 5Storage Before Replication= 1,351.833 GB
- 6Daily Volume= 193.119 GB
- 7Messages Retained= 3,024,000,000
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 or fees or charges into account.
- Figures are rounded for display to 4 decimal places, 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 Message Queue Size calculated?
Storage = rate × retention seconds × compressed message size × replication factor Queue storage multiplies by the replication factor, so a three-times replicated topic needs three times the raw volume. Retention is usually the largest and most adjustable term.
Why does Message Queue Size matter?
Log-based brokers retain messages after consumption to allow replay, which makes retention a storage decision rather than a delivery one.
What values do I need to enter?
This calculator takes 5 inputs: Messages per second, Average message size, Retention period, Replication factor, Compression saving. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.