Chess strength is only well defined when talking about a particular time control: Magnus, like any player, makes more mistakes and plays weaker moves on average in fast games than in slow games. Because games in the Play Magnus app are untimed, it is therefore not possible to quantify exactly how strong the individual levels are. Another difficulty when estimating the strength of the levels is that it is not really possible without playing a large number of serious games between the app and human players of known Elo ratings. However, the progression from level to level is designed to roughly correspond to Magnus' rate of improvement at that age. The exception is the levels from around 10 to 16, where we have flattened the curve somewhat in order to make it easier for everybody to find a level close to their own strength.