Pick the right refrigerator volume in litres for your household size.
Refrigerator sizing starts from a base for the first person and adds per head, because the fixed items — condiments, dairy, leftovers — do not scale with household size while fresh produce and drinks do. Roughly 200 litres covers one adult's fixed load, each additional adult adds about 70 litres and each child about 50. Shopping habits then shift the answer more than family size does: a weekly bulk shop needs somewhere to put a week of food, and regular batch cooking needs freezer volume rather than shelf space. Splitting the total into roughly 70% fresh food and 30% freezer matches how most fridge-freezers are built, so the two figures tell you which configuration to look for.
Fridge Size for Family
Litres = 200 + 70 per extra adult + 50 per child + 80 if bulk shopping + 60 if entertaining; cubic feet = litres / 28.32
About 70 for an adult and 50 for a child on top of a 200 litre base — so a family of four lands near 420 litres, or 15 cu ft, before allowing for bulk shopping.
Less than an overfull one. A cramped fridge blocks airflow and forces the compressor to run longer, whereas a larger cabinet with good circulation often uses similar energy for the same contents.