Encher vs. inflar vs. insuflar
While encher, inflar, and insuflar all relate to the action of filling something with air or gas, usage depends heavily on the region (Brazil vs. Portugal) and the register (casual vs. technical). Encher is the universal colloquial term, while the other two have specific regional preferences for technical descriptions and derived nouns.
Encher
A2This is the most common, everyday verb used in both Brazil and Portugal. Although strictly meaning to fill (with anything, including water or solids), when applied to tires, balloons, or balls, it functions as the standard word for to inflate. usage is informal to neutral.
Preciso parar no posto para encher os pneus do carro.
(I need to stop at the gas station to fill up the car tires.)
As crianças ajudaram a encher os balões para a festa.
(The children helped blow up the balloons for the party.)
Ele teve que encher o colchão de ar com a boca.
(He had to fill the air mattress with his mouth.)
Inflar
B2This verb means to inflate or to swell. It is widely used in Brazil for everyday objects (like inflatable pools or boats). In Portugal, it is less common for physical objects (where encher or insuflar are preferred) and is often reserved for technical contexts or metaphorical expansion (like economic inflation). In Brazil, the adjective inflável (inflatable) is standard.
O colete salva-vidas inflou automaticamente ao tocar na água.
(The life jacket inflated automatically upon touching the water.)
Compramos uma piscina inflável para o verão.
(We bought an inflatable pool for the summer.)
O sapo infla o papo para atrair a fêmea.
(The frog puffs up its throat pouch to attract the female.)
Insuflar
C1Literally meaning to blow into or to insufflate, this word is technical or medical in Brazil. However, in Portugal, it is the standard term for larger inflatable structures. Crucially, the adjective insuflável is the European Portuguese standard for inflatable (in contrast to the Brazilian inflável).
No parque havia um enorme castelo insuflável para as crianças.
(In the park, there was a huge bouncy castle (inflatable castle) for the children.)
O médico precisou insuflar ar na cavidade abdominal para a cirurgia.
(The doctor needed to insufflate air into the abdominal cavity for the surgery.)
Em Portugal, é comum alugar escorregas insufláveis para eventos.
(In Portugal, it is common to rent inflatable slides for events.)
Summary
To sound natural: use encher for simple acts like filling tires or balloons in both countries. Use inflar and the adjective inflável in Brazil for distinct objects (mattresses, pools). Use insuflar and the adjective insuflável in Portugal for those same objects.