In Spanish, the letters B and V are pronounced exactly the same. There is no audible difference between vaca (cow) and a hypothetical baca, or between tubo (tube) and tuvo (he had). Native speakers sometimes joke about this — when spelling out loud, they clarify by saying b de burro ("b as in donkey") or v de vaca ("v as in cow").
Because you cannot hear the difference, you must memorize the spelling of each word. The good news is that there are reliable patterns that cover most cases.
The basic rule: it is all about origin
Both letters come from Latin, and each word generally keeps the spelling it had in Latin. Latin vacca became Spanish vaca. Latin bonus became Spanish bueno. You do not need to study Latin, but you can use modern patterns as shortcuts.
La vaca come hierba.
The cow eats grass.
El libro es nuevo.
The book is new.
When to use B
After the letter M
Spanish almost never writes mv. If you hear an [m] followed by a [b] sound, it is written mb.
también
also
hombre
man
cambio
change
The suffixes -bilidad and -bundo/-bunda
Abstract nouns ending in -bilidad always take b. Adjectives ending in -bundo or -bunda do too.
| Suffix | Example | Meaning |
|---|---|---|
| -bilidad | posibilidad | possibility |
| -bilidad | amabilidad | kindness |
| -bundo | vagabundo | vagabond |
| -bunda | moribunda | dying (fem.) |
Verbs ending in -bir and -buir
Verbs whose infinitive ends in -bir or -buir keep the b through all their forms.
Quiere contribuir al proyecto.
He wants to contribute to the project.
The main exceptions you must memorize are: hervir, servir, and vivir. These three end in -vir, not -bir.
The imperfect tense of -ar verbs
Every -ar verb forms its imperfect with -aba, -abas, -aba, -ábamos, -aban. Always b.
Cantaba en el coro.
I used to sing in the choir.
When to use V
After the letter N
The reverse of the mb rule. If you hear [n] followed by [b], write nv.
Voy a enviar el paquete.
I am going to send the package.
Me invitaron a la fiesta.
They invited me to the party.
The suffixes -ivo and -iva
Most adjectives ending in -ivo or -iva take v.
| Word | Meaning |
|---|---|
| activo | active |
| creativa | creative |
| positivo | positive |
| decisivo | decisive |
Verbs ending in -ervar and -ivar
Verbs with these endings almost always take v: conservar, observar, reservar, cultivar, activar, motivar.
Irregular preterite stems with v
Several common irregular verbs use v in their preterite and imperfect subjunctive stems: estuve/estuviera (estar), tuve/tuviera (tener), anduve/anduviera (andar).
Common confusion pairs
Some words differ by only b/v and have completely different meanings. Context will almost always tell you which is which, but be careful in writing.
| With B | With V |
|---|---|
| tubo (tube) | tuvo (he had) |
| baca (roof rack) | vaca (cow) |
| bello (beautiful) | vello (body hair) |
| basto (coarse) | vasto (vast) |
Related Topics
- B and VA1 — B and V are pronounced identically in Spanish
- Spelling Rules OverviewA1 — An introduction to Spanish spelling rules and the letters that cause the most confusion