Using poder in the preterite vs the imperfect in Spanish (could in past actions)

We can use the modal verb poder (to be able to) for past actions in both El Pretérito Indefinido and in El Pretérito Imperfecto. However poder has different meanings depending on which tense you use.

Have a look and listen to these examples:

Ella podía ayudar a su amiga.She could help her friend.

Ella pudo ayudar a su amiga.She could/managed to help her friend.

When poder is used in El Pretérito Indefinido, it has the nuance of "succeeding/managing (or not) to do something".

Let's compare these other examples:

Javier no pudo abrir la puerta. 
Javier didn't succeed in opening the door.

Javier no podía abrir la puerta. 
Javier couldn't open the door.

In the first example above with "pudo" we know the result, but in the second one with "podía" we don't know whether he managed to open the door or not, we only know that he was not able to open the door at that time.

Have a look at other examples using El Pretérito Indefinido:

No pude hablar con ella ayer porque la señal en mi casa era débil.I couldn't / didn't manage to talk to her yesterday because the signal in my house was poor.

Los ingenieros no pudieron arreglar el problema.The engineers couldn't fix / didn't succeed in fixing the problem.

Angela pudo obtener una plaza en el taller de dibujo.Angela could / managed to get a space at the drawing workshop.

Ustedes no pudieron llegar a tiempo a la estación.You didn't manage to get to the station on time.

Have a look at other examples using El Pretérito Imperfecto:

Carlos no podía hablar con ella porque estaba nervioso.Carlos could not talk to her because he was nervous.

Gabriel no podía meter las llaves en la cerradura anoche.Gabriel couldn't put the keys in the keyhole last night.

Vosotros podíais espiar al vecino por la ventana.You could spy on the neighbour through the window.

Ustedes no podían comprar nada en el mercado.You couldn't buy anything in the market.

Remember that whichever tense is used with poder, it is always followed by Infinitivo

See also:

Want to make sure your Spanish sounds confident? We’ll map your knowledge and give you free lessons to focus on your gaps and mistakes. Start your Brainmap today »

Examples and resources

Ella podía ayudar a su amiga.She could help her friend.
Ella pudo ayudar a su amiga.She could/managed to help her friend.
Vosotros podíais espiar al vecino por la ventana.You could spy on the neighbour through the window.
Carlos no podía hablar con ella porque estaba nervioso.Carlos could not talk to her because he was nervous.
No pude hablar con ella ayer porque la señal en mi casa era débil.I couldn't / didn't manage to talk to her yesterday because the signal in my house was poor.
Angela pudo obtener una plaza en el taller de dibujo.Angela could / managed to get a space at the drawing workshop.
Los ingenieros no pudieron arreglar el problema.The engineers couldn't fix / didn't succeed in fixing the problem.
Ustedes no pudieron llegar a tiempo a la estación.You didn't manage to get to the station on time.
Ustedes no podían comprar nada en el mercado.You couldn't buy anything in the market.
Gabriel no podía meter las llaves en la cerradura anoche.Gabriel couldn't put the keys in the keyhole last night.
I'll be right with you...