Concurrency Capacity Planner
Size concurrency and instances for a target request rate.
Results update automatically as you type.
Result
60 concurrent requests needed
≈ 6 instances at 10 concurrent each
- Target throughput
- 20 req/s
- Avg latency
- 3 s
- Concurrency (Little's law)
- 60
- Instances
- 6
Use Little's law to size your deployment: enter target requests/second and average latency to see the concurrency needed, and how many instances that requires.
How this is calculated
This calculator uses the infrastructure formulas described in our methodology. All figures are estimates for planning; verify current pricing with each provider before relying on them.
Worked example (defaults)
With the default inputs above, here is the result:
Result
60 concurrent requests needed
≈ 6 instances at 10 concurrent each
- Target throughput
- 20 req/s
- Avg latency
- 3 s
- Concurrency (Little's law)
- 60
- Instances
- 6
Frequently asked questions
What is Little's law?+
Concurrency = throughput × latency. To serve 20 req/s at 3s each, you need ~60 requests in flight.
How many instances do I need?+
Divide required concurrency by how many concurrent requests each instance handles, then round up.