Complete Contractions Reference

This is your one-stop reference for every preposition contraction in Brazilian Portuguese. The big idea — and the thing English gives you no preparation for — is that only four prepositions fuse with following words: de, em, a, and por. Every other preposition (com, sem, sobre, entre, até, para, contra, desde) stays fully separate from whatever follows it. English contracts almost nothing at the preposition level (we say of the, not o'the), so this whole apparatus is new territory; bookmark this page and come back to it until the forms are automatic.

We will go preposition by preposition, then collect the special pronoun fusions, then mark clearly what is mandatory versus optional versus nonexistent.

de — the most prolific contractor

De fuses with the widest range of words: articles, demonstratives, the locative adverbs, and the third-person pronouns. Every fusion below is mandatory in standard writing.

em — same reach as de

Em contracts with exactly the same set of words as de, swapping the d- for an n-. If you learn one paradigm, you nearly get the other for free.

a — fewer fusions, and the all-important crase

A is more limited. It fuses with the feminine articles and with the demonstratives that begin with a-. The most important — and the one with its own diacritic — is a + a → à, the grave accent known as crase. The masculine a + o → ao is also mandatory but takes no accent.

Note that a does not contract with personal pronouns: a ele, a ela stay separate (you cannot write "àle"). The crase only appears when the preposition a meets a word that itself begins with the a-sound of an article or aquele-type demonstrative.

por — only the article, and in disguise

Por fuses only with the definite article, producing the deceptive p-l forms inherited from the old preposition per. It never touches pronouns or demonstratives (see the dedicated page).

The prepositions that NEVER contract

This is the half of the table learners most often get wrong by overgeneralizing. The following prepositions stay completely separate from articles, pronouns, and everything else. Write com o, sem a, sobre os, entre as — never a fused form.

The pronoun fusions: comigo, contigo, conosco

A separate, irregular family exists for com + a personal pronoun. These are not the regular contractions above — they are old fused forms, and they are mandatory. You cannot say "com mim"; it must be comigo.

These are the only place com ever fuses — with these specific pronouns, never with a noun or article. The full mechanics live on the dedicated comigo/contigo page.

Optional and informal forms

Two categories sit outside the "mandatory" world:

• Optional written contractions: de/em + um → dum/num, duma/numa. These are correct but slightly informal; careful prose often keeps de um, em um uncontracted. Both are accepted.
• Spoken-only reductions of para: pra (= para a / para), pro (= para o), pros/pras. These dominate casual speech and texting but are (informal) — they do not belong in formal writing, where you write para in full.

Common Mistakes

Key Takeaways

• Only de, em, a, por contract with the article. Everything else (com, sem, sobre, entre, até, para, contra, desde) stays separate.
• de and em reach the furthest — articles, demonstratives, third-person pronouns, locative adverbs.
• a gives you the crase (à, às, àquele); it does not touch personal pronouns.
• por fuses only with the article (pelo/pela/pelos/pelas), never with pronouns.
• comigo, contigo, consigo, conosco are the irregular mandatory fusions of com
  • pronoun.
• dum/num are optional; pra/pro are informal-spoken only.