Numbers in Portuguese: zero to a billion, Brazilian and European forms

How Portuguese builds numbers: e between every part

From twenty on, numbers in Portuguese join tens and units with e, and: vinte e um (21), trinta e dois (32), noventa e nove (99). The same e links hundreds to the rest, cento e vinte (120), and keeps going in long numbers: mil novecentos e oitenta e quatro is 1984.

One hundred has two forms, and Wiktionary's usage note sets out when each applies. Cem stands alone, before a noun and before a higher number: de um até cem, cem pessoas, cem mil. Cento appears only in compounds followed by a smaller number: cento e duas pessoas, a hundred and two people. From two hundred on the hundreds are single words, several of them irregular: duzentos, trezentos, quinhentos.

The teens 11 to 15 are inherited Latin forms, onze to quinze, all ending in -ze. From 16 the language counts ten and six, ten and seven, and this is where Brazil and Portugal part.

Dezesseis or dezasseis: Brazilian and European forms

Sixteen is dezesseis in Brazil and dezasseis in Portugal, and seventeen and nineteen follow the same split: dezessete and dezenove against dezassete and dezanove. Wiktionary derives the Brazilian forms from dez e seis, ten and six, and the European ones from a pattern going back to Latin decem ac sex, ten and six with a different conjunction. Eighteen is dezoito everywhere. Both sets are correct, each in its own country; Wiktionary's table of Portuguese numbers labels them Brazil and Portugal.

Fourteen has the two spellings catorze and quatorze, with quatorze listed as an alternative form. The difference in sound follows the general pattern of the two varieties: in European Portuguese the unstressed e of dezoito and sessenta shrinks to a short ɨ, and the final -e of sete, nove and vinte is almost silent, while Brazil pronounces that final -e as i, which turns te and de into the sounds tchi and dji: sete is [ˈsɛ.t͡ʃi], vinte [ˈvĩ.t͡ʃi].

In Brazil, when phone numbers and codes are read out digit by digit, six is often replaced by meia, short for meia dúzia, half a dozen. Wiktionary's usage note explains the reason: seis rhymes with três and the two are easily confused.

Gender: um or uma, dois or duas

Um and dois have feminine forms, uma and duas, and the choice depends on the noun counted: um livro, uma casa, dois livros, duas casas. Compounds keep the agreement, vinte e uma pessoas, twenty-one people, and so does cento e duas pessoas from the Wiktionary example above. Um doubles as the indefinite article, a or an, so uma casa means both a house and one house.

The other numbers up to a thousand have one form. Large numbers behave like nouns: milhão and bilhão are masculine and take de before a noun, um milhão de habitantes, a million inhabitants, while mil takes no article and no de: mil pessoas.

Bilhão or mil milhões: the long and short scales

The biggest trap among numbers in Portuguese is the billion. Brazil uses the short scale, as English does: um bilhão is 10⁹, a thousand million. Portugal and the African Portuguese-speaking countries use the long scale: 10⁹ is mil milhões, a thousand million, and um bilião is 10¹², what English calls a trillion. Wiktionary's usage notes record this, adding that the Angolan government prescribes the long scale.

A news report about bilhões therefore means different amounts depending on where it was written. European texts prefer the spelling bilião, with li, for 10¹², and treat bilhão as an informal variant of it. In Brazil 10¹² is um trilhão.

Decimal comma and digit grouping

Portuguese writes a comma for the decimal point: 3,5 is three and a half, read três vírgula cinco. The Unicode CLDR locale data shows a difference in grouping: Brazilian Portuguese separates thousands with a dot, 1.234.567, and European Portuguese with a space, 1 234 567. CLDR's Portugal data also sets a minimum of two grouping digits, so a four-digit number such as 2026 or 1500 is printed without any separator.

Zero comes from French zéro, through Italian and Medieval Latin from Arabic ṣifr, according to Wiktionary. The same Arabic word is behind sifar, one of the two words for zero in Hindi.