Mezzo vs. metà
While both words translate to "half" in English, the difference lies in their grammatical function. Generally, mezzo acts as an adjective describing a noun (half a...), while metà acts as a noun representing a 50% portion or a midpoint (the half).
Mezzo
A1This word functions primarily as an adjective meaning "half a" or "partial". Because it is an adjective, it usually precedes the noun and agrees with it in gender and number (changing to mezza, mezzi, or mezze). It expresses a quantity or a state of being incomplete.
Ho comprato mezzo chilo di fragole.
(I bought half a kilo of strawberries.)
È già passata mezz'ora da quando sei uscito.
(Half an hour has already passed since you left.)
Non fare le cose a mezzo servizio.
(Do not do things with half measures.)
Vorrei una mezza porzione di pasta.
(I would like a half portion of pasta.)
Lascia la porta socchiusa o mezza aperta.
(Leave the door ajar or half open.)
Metà
A1This word is a noun that means "the half" or "the middle". It refers to the concept of dividing a whole into two equal parts (50%) or reaching a center point. It is strictly singular and usually follows a preposition or an article like la (the).
Taglia la torta esattamente a metà.
(Cut the cake exactly in half.)
Ho letto solo la metà del libro.
(I only read half of the book.)
La metà di otto è quattro.
(Half of eight is four.)
Siamo arrivati a metà strada.
(We have reached the halfway point.)
Il giocatore ha fatto fallo nella sua metà campo.
(The player committed a foul in his half of the field.)
Summary
Use mezzo as an adjective when modifying a specific object (e.g., "half an apple"). Use metà as a noun when referring to the mathematical segment or the division itself (e.g., "the half of the apple" or "split in half").