Is it written all’incirca or allincirca?

The correct form is all’incirca, written detached and with an apostrophe.

The expression circa derives from the adverb “incirca”, composed of the simple preposition “in” and the word “circa” which means “pressapoco”. In fact all’incirca is used to indicate an approximate quantity.

Ho comprato all’incirca un chilo di pane.

Arriverò al ristorante all’incirca alle otto di sera.

La spesa totale sarà di 500 euro all’incirca.

Allincirca, written all attached and without the apostrophe, does not exist in Italian and is incorrect.

See also:

Is it written un po’ or un pò?

Test yourself with the following practical exercise:

Un po’, un pò, all’incirca o allincirca: vero o falso?