### In Investment, the Rule of 72

The Rule of 72 is a simple calculation used in accountancy and investment. Simply, if you divide the interest rate by 72 you get the number of periods your investment will double. I have £100 and an interest rate of 10% per year then it will take 7.2 years (72/10 = 7.2) for my money to double.

### In Realtime and Streaming Applications

Workflow throughput is everything. How consumers perform and behave will have a knock on effect to the number of messages you can process. So please allow me to present, The Streaming Rule of 72.

*In realtime and streaming applications, the rule of 72, the rule of 70 and the rule of 69.3 are methods for estimating the volume of messages able to be processed doubling time. The rule number (e.g., 72) is divided by the percentage gain per period to obtain the approximate number of periods (usually seconds) required for doubling.*

For example if 100 messages are flowing through the system per second and by changing the workflow timeouts, increase a container shared memory volume or extend a heartbeat time out for example, then measure throughput again and we process 130 messages a second. That’s a 30% increase ((130-100)/100) so with the streaming rule of 72….. we will double the message volume every 2,4 seconds.