The age distribution, , in Mägenwil is; 223 children or 12.1% of the population are between 0 and 9 years old and 266 teenagers or 14.4% are between 10 and 19. Of the adult population, 217 people or 11.8% of the population are between 20 and 29 years old. 285 people or 15.5% are between 30 and 39, 349 people or 19.0% are between 40 and 49, and 212 people or 11.5% are between 50 and 59. The senior population distribution is 151 people or 8.2% of the population are between 60 and 69 years old, 104 people or 5.6% are between 70 and 79, there are 29 people or 1.6% who are between 80 and 89,and there are 5 people or 0.3% who are 90 and older.