Ammerswil has a population () of . , 10.8% of the population are foreign nationals. Over the last 10 years (1997–2007) the population has changed at a rate of 24.5%. Most of the population () speaks German (96.6%), with Italian being second most common ( 1.6%) and Portuguese being third ( 0.8%). The age distribution, , in Ammerswil is; 65 children or 9.9% of the population are between 0 and 9 years old and 87 teenagers or 13.2% are between 10 and 19. Of the adult population, 77 people or 11.7% of the population are between 20 and 29 years old. 95 people or 14.4% are between 30 and 39, 135 people or 20.5% are between 40 and 49, and 92 people or 14.0% are between 50 and 59. The senior population distribution is 57 people or 8.6% of the population are between 60 and 69 years old, 35 people or 5.3% are between 70 and 79, there are 14 people or 2.1% who are between 80 and 89, and there are 2 people or 0.3% who are 90 and older. the average number of residents per living room was 0.55 which is about equal to the cantonal average of 0.57 per room. In this case, a room is defined as space of a housing unit of at least as normal bedrooms, dining rooms, living rooms, kitchens and habitable cellars and attics. About 65.6% of the total households were owner occupied, or in other words did not pay rent (though they may have a
mortgage or a
rent-to-own agreement). , there were 12 homes with 1 or 2 persons in the household, 79 homes with 3 or 4 persons in the household, and 127 homes with 5 or more persons in the household. There were a total of 1 empty apartments for a 0.4% vacancy rate. ==Heritage sites of national significance==