Load Assumptions

Before designing, we estimate the load. These numbers are my assumptions, not the real numbers of any chess site. I checked the real sites on Oct 31, 2026, to keep the assumptions in a reasonable range.

Players

We assume 20 million rated players in a time control. That counts every player with a rating, whether they still play or not. Chess.com is about this size: it had over 252 million members in March 2026, and about 10 million people played on it each day.

Games and rating changes

We assume 10 million games a day. Lichess says it hosts over 5 million games a day. Chess.com reported 2.5 billion games in the last three months of 2025. That is about 27 million a day.

A day has 86,400 seconds. For a quick estimate, we round that up to 100,000. So 10 million games a day is about 100 games a second.

Games are not spread evenly over the day. More people play in the evening and on weekends. We assume the peak is five times the average: 500 games a second.

Each game changes two ratings. So at the peak, 1,000 ratings change a second.

Open pages

We assume about 10 million players play on a given day, as on Chess.com. At the peak, we assume 1 percent of them have a page of the leaderboard open. That is 100,000 open pages.

Memory

Each player on the leaderboard needs a player ID, a rating, and a username. With the structures that keep them in order, we assume about 100 bytes a player.

• 20 million players × 100 bytes is 2 billion bytes, about 2 GB for one time control.
• Three time controls take about 6 GB.

6 GB fits in the memory of one server.