Signification
As a precaution, in case something happens.
Contexte culturel
In Spain, 'por si las moscas' is ubiquitous. It's said that it comes from the habit of covering food with a cloth to keep flies away, even if there are no flies visible at the moment. Mexicans often use 'por si las dudas'. It sounds slightly more cautious and is used in everything from business to family life. In Argentina, you might hear 'por las dudas' (dropping the 'si'). It's a very common shorthand in Buenos Aires. In some regions, a 'por si acaso' is a physical object—a small bag of food or essentials kept for an emergency or a long trip.
The Standalone Rule
If you are unsure of the grammar, just put 'por si acaso' at the very end of your sentence. It almost always works!
Avoid 'Para'
Never say 'para si acaso'. It's a dead giveaway that you are translating literally from another language.
Signification
As a precaution, in case something happens.
The Standalone Rule
If you are unsure of the grammar, just put 'por si acaso' at the very end of your sentence. It almost always works!
Avoid 'Para'
Never say 'para si acaso'. It's a dead giveaway that you are translating literally from another language.
Politeness Hack
Use 'por si acaso' to ask someone to double-check something without sounding bossy. 'Mira el mapa, por si acaso'.
Teste-toi
Complete the sentence with the correct phrase.
Llevo el mapa ____.
'Por si acaso' is the standard neutral phrase for 'just in case'.
Which sentence is more natural for a casual conversation with friends?
I'm bringing extra snacks just in case.
'Por si las moscas' is a very common informal variation.
Match the action to the 'por si acaso' reason.
Action: 'Guardo el teléfono en una bolsa de plástico.'
Plastic bags protect electronics from rain.
What would the second speaker say?
A: ¿Por qué compraste dos entradas? B: ________.
This uses 'por si acaso' followed by a clarifying clause correctly.
🎉 Score : /4
Aides visuelles
Banque d exercices
4 exercicesLlevo el mapa ____.
'Por si acaso' is the standard neutral phrase for 'just in case'.
I'm bringing extra snacks just in case.
'Por si las moscas' is a very common informal variation.
Action: 'Guardo el teléfono en una bolsa de plástico.'
Plastic bags protect electronics from rain.
A: ¿Por qué compraste dos entradas? B: ________.
This uses 'por si acaso' followed by a clarifying clause correctly.
🎉 Score : /4
Questions fréquentes
10 questionsIt is neutral. You can use it with your boss or your best friend.
Yes, but it's less common. Usually, you'd say 'Por si acaso, he traído esto'.
'Por si acaso' is standalone. 'Por si' must be followed by a verb or noun (e.g., 'por si llueve').
It's a funny, informal way to say 'just in case', referring to keeping flies off food.
No, 'por si' is almost always followed by the indicative mood in common speech.
Yes, it is universally understood and used everywhere.
No, it's for future possibilities. For the past, you'd say 'lo hice por precaución'.
Yes, it's the preferred version in Argentina and Uruguay.
Yes, but it means 'perhaps' or 'by any chance' and is more formal.
Use 'como medida de precaución' or 'en previsión de'.
Expressions liées
Por si las moscas
synonymJust in case (informal)
En caso de que
similarIn the event that
Por si las dudas
synonymJust in case (Americas)
Prevenir es mejor que lamentar
builds onBetter safe than sorry
