Numbers you can do in your head

Start with people

Say 30 million people use your app a month and each visit makes 20 requests. Not everyone visits daily; a third do, so 10 million visitors a day. That is 200 million requests a day (all numbers approx.).

Divide by a day, then by the peak

Change the visitors, requests and peak. Follow the units from one day to one second before adding spare capacity.

Try the idea

Peak is 9,000 requests a second. Serve it with at least 25% spare app capacity.

Key numbers

Seconds in a day

≈ 100,000. 86,400, rounded for easy math

1 million requests a day at 2 KB each

≈ 2 GB a day. 2 KB × 1,000,000

One server

≈ 1,000 requests a second. typical web API, approx.

Check your reasoning

Think through these questions before opening the lesson. In the game you can test the idea and compare your reasoning.

• About how many seconds are in a day, for quick math?
• Average load is 2,000 requests a second. Peak is often about:
• One server handles 1,000 requests a second and you need 9,000. How many do you run?