Portuguese Number to Words

Is 200 duzentos or duzentas? Is 1,000,000,000 bilhão or mil milhões? Both — depending on the gender of the noun and which side of the Atlantic your reader is on. Portuguese number-spelling (por extenso) carries gender agreement in the hundreds, an irregular cem/cento split, non-uniform e connectors, and a Europe-vs-Brazil scale divergence that naive converters reliably get wrong. This tool applies all four rule systems and switches cleanly between European and Brazilian forms.

The grouping algorithm

The number is split into three-digit groups from the right. Each group is read with its hundreds, tens, and units, joined internally by e. Then the groups are combined with scale words (mil, milhão, bilhão and so on) and the inter-group e rule:

123       → cento e vinte e três
200 (f)   → duzentas
1000      → mil            (not "um mil")
1200      → mil e duzentos
1230      → mil duzentos e trinta
2 000 000 → dois milhões

Only the lowest group takes the gender you select; higher groups read in the masculine, because the scale words themselves are masculine.

The rules that catch people out

Cem vs cento

Exactly one hundred is cem. The moment anything is added, it becomes cento:

• 100 → cem
• 101 → cento e um
• 150 → cento e cinquenta
• 200 → duzentos (a separate word — not dois centos)

Gender in the hundreds

From 200 to 900, the hundreds words change form to agree with the noun being counted:

Only the lowest group (the units group) inherits the gender you select; scale words like mil and milhões are grammatically invariable.

The e connector rule

Portuguese uses e (and) to join parts within and between groups, but the placement is not uniform:

• Within a group: always — cento e vinte e três
• Between groups when the last group is below 100 or a round hundred: insert e — mil e duzentos, mil e cinquenta
• Between groups when the last group is between 101–999 and not a round hundred: no e before the group — mil duzentos e trinta

Dropping um before mil

Portuguese drops the numeral one before mil. So 1,000 is just mil, not um mil. The same applies in the European long-scale form: mil milhões (not um mil milhões).

European versus Brazilian

Switch on European Portuguese to get dezasseis, dezassete, and dezanove in the teens, and the long-scale large numbers: mil milhões for 10^9 and bilião for 10^12. Brazilian Portuguese keeps dezesseis and the short scale, where bilhão already means 10^9.

The default settings are masculine and Brazilian; flip the gender for feminine nouns such as duas cadeiras or duzentas páginas. Flip the EU toggle for European contracts, legal documents, or journalistic copy.

Where por extenso is actually required

Spelled-out numbers are not a stylistic flourish in Portuguese — they are mandatory or customary in several formal contexts: cheque amounts (the written words control over the digits when they disagree), notarial deeds and property contracts, powers of attorney, court filings, and invoice totals in some corporate templates. In these documents a gender error (duzentos euros is fine, but duzentas euros is wrong because euro is masculine) or the wrong scale word in a cross-Atlantic contract (bilhão meaning 10⁹ to a Brazilian reader but a long-scale 10¹² to an older European one) is exactly the kind of ambiguity the por-extenso requirement exists to remove. When drafting for both markets, prefer unambiguous forms — mil milhões or explicit digits alongside the words.

Sources

• Ciberdúvidas da Língua Portuguesa — the reference consultancy on Portuguese usage, including numerals, gender agreement, and the e connector
• Dicionário Priberam da Língua Portuguesa — dictionary entries showing both European and Brazilian forms (dezasseis/dezesseis)

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