Pretérito Indefinido vs Imperfecto in Spanish

Both the pretérito indefinido and pretérito imperfecto talk about the past, but they show past actions in different ways.

A useful beginner rule is:

• Indefinido → what happened
• Imperfecto → what was happening, used to happen, or what things were like

The main difference

Use the pretérito indefinido for completed past events.

• Ayer fui al supermercado. — Yesterday I went to the supermarket.
• Llegó a las ocho. — He arrived at eight.
• Viví en Madrid durante dos años. — I lived in Madrid for two years.

Use the pretérito imperfecto for background, habits, descriptions, and ongoing situations.

• De pequeña, vivía en Madrid. — When I was little, I lived in Madrid.
• Siempre iba al parque después de clase. — I always used to go to the park after class.
• Hacía frío y llovía. — It was cold and raining.

Completed event vs ongoing background

A common pattern is:

imperfecto + cuando + indefinido

The imperfecto describes what was already happening. The indefinido introduces the completed event.

• Dormía cuando sonó el teléfono. — I was sleeping when the phone rang.
• Cocinábamos cuando llegó Marta. — We were cooking when Marta arrived.
• Caminaba por la calle cuando empezó a llover. — I was walking down the street when it started to rain.

The action in the imperfecto provides the background, while the indefinido moves the story forward.

Habit vs specific event

Compare:

• Antes iba al gimnasio todos los días. — I used to go to the gym every day.
• Ayer fui al gimnasio. — I went to the gym yesterday.

Use the imperfecto for a habit and the indefinido for a specific completed event.

Description vs change

The imperfecto often describes a situation or state. The indefinido can show that something changed.

• La puerta estaba abierta. — The door was open.
• Ana abrió la puerta. — Ana opened the door.
• Era muy tímido de pequeño. — He was very shy as a child.
• Un día decidió hablar con ella. — One day he decided to talk to her.

Time expressions can help

Some expressions often appear with the indefinido because they refer to a specific completed period:

• ayer — yesterday
• anoche — last night
• la semana pasada — last week
• en 2025 — in 2025
• una vez — once

Some expressions often appear with the imperfecto because they describe habits or repeated situations:

• siempre — always
• normalmente — normally
• a menudo — often
• todos los días — every day
• de pequeño/a — when I was little
• antes — before / in the past

These expressions are helpful clues, but they do not automatically decide the tense. The meaning of the sentence is more important.

Compare the same verb

Sometimes the same verb can appear in either tense depending on the meaning.

• Vivía en Sevilla. — I lived / was living in Seville.
• Viví en Sevilla durante tres años. — I lived in Seville for three years.
• Leía mucho de pequeña. — I used to read a lot as a child.
• Leí ese libro el mes pasado. — I read that book last month.

The imperfecto presents the situation as background or habitual. The indefinido presents it as a completed event or period.

Quick comparison

Pretérito indefinido	Pretérito imperfecto
completed event	ongoing situation
specific past action	repeated habit
event that moves the story forward	background information
beginning or end of an action	description or state
Ayer fui al cine.	Antes iba mucho al cine.

Quick rule

Ask yourself:

Am I telling the reader what happened, or describing what was happening / what things were like?

• What happened? → indefinido
• What was happening / used to happen / was it like? → imperfecto

For the forms and uses of each tense, see Pretérito Indefinido and Pretérito Imperfecto.