Denderleeuw covers 13.9 km² and has 20,338 inhabitants. The population’s average age is about 40, and women represent 50.9%. Home ownership stands at 74%, while average net income is €19,054 per person per year. The population includes 91.9% Belgian, 1.5% Dutch, 1.1% Congolese, 0.7% Romanian, 0.6% Cameroonian, 0.5% Polish, 0.4% Turkish and 3.4% other nationalities. Households own an average of 1.2 cars.
Houses represent 77.7% of dwellings in the municipality, compared with 22.3% in apartment buildings. The average home has 5.6 rooms, and buildings have an average construction year of 1963. Across building types, 32.9% are closed houses, 31.4% semi-closed houses, 21.6% buildings and flat blocks, 10.9% open houses, farms and castles, 2.4% commercial houses and 0.8% other types. There are currently 0 houses for rent. The stated average monthly rent is €0, with both the highest and lowest listed monthly rent also given as €0.
The N208 and N405 serve the municipality. The nearest stated A10/E40 motorway entrance, on the route linking Brussels, Aalst, Ghent, Bruges and Ostend, is 6 minutes by car from the town centre. An entrance to the R0 Brussels ring is 12 minutes away by car. Bus services listed include De Lijn lines 31, 32, 33 and 330 and the NMBS/SNCB BUS line. Stations in the area include Iddergem, Denderleeuw, Liedekerke, Welle and Okegem. No metro or tram is listed. Brussels Airport is 24 minutes away by car and 93 minutes by public transport.
Denderleeuw has 6 nurseries, 8 nursery schools, 8 primary schools and 4 secondary schools. Examples include De Bengeltjes, Partena Kinderdagverblijven - Doedeldorp, Vrije Basisschool - 'T Landuiterke, Go! Basisschool De Wereldboom, Vrije Basisschool Kcd, Leonardo College and Go! Atheneum Denderleeuw. Grocery shopping includes 2 Aldi, 2 Delhaize, 1 Louis Delhaize, 1 OKay, 1 SPAR and 1 Carrefour. There are no shared bicycles or shared cars in the municipality at present, and no charging station for electric vehicles is known there.