Duffel is a municipality in the Belgian province of Antwerp. The municipality comprises the town of Duffel proper. On 1 January 2020, …Duffel is a municipality in the Belgian province of Antwerp. The municipality comprises the town of Duffel proper. On 1 January 2020, Duffel had a total population of 17,664. The total area is 22.71 km² which gives a population density of 778 inhabitants per km².