“Keep” is the base form of the verb. “Kept” is the past simple and past participle form. Use “keep” for present and future meanings, and use “kept” for finished past time or for perfect and passive structures that need a past participle.

Use “keep” to talk about habits, repeated actions, and general truths. It also works for instructions and rules in the present. The idea is that the action continues or is generally true, not finished at a past time.

Use “keep” to express future plans or promises, often with “will” or “going to.” This is common when you are talking about continuing a behavior in the future. The verb stays as “keep” because the tense is carried by the auxiliary.

Use “kept” for a completed action in the past, often with a clear past time reference or a finished situation. This form tells the listener the action happened and ended in the past. It can describe actions, decisions, or states that were true before but may not be true now.

Subject	Form	Example
I	kept	I kept the receipt.
you	kept	You kept your promise.
he	kept	He kept the door locked.
she	kept	She kept the photo.
it	kept	It kept working all day.
we	kept	We kept our seats.
they	kept	They kept quiet.

Use “kept” after “have” or “had” to form the present perfect or past perfect. These forms connect a past action to the present, or place one past action before another past moment. “Kept” is required because it is the past participle.

Use “kept” with “be” to form passive meaning, where the subject receives the action. This is common in phrases like “be kept” meaning something is stored, maintained, or continued by someone. The past participle “kept” signals the passive structure.

“Keep” often means to continue doing something, especially with “keep + -ing.” This expresses repetition or persistence over time, not one single event. The tense changes with auxiliaries, but the main verb remains “keep.”

“Keep” can mean to store, retain, or not throw away. In this meaning, “kept” describes what you stored in the past or what has been retained up to now in perfect forms. The focus is on possession or retention rather than action.

“Keep” can mean to maintain a state or condition, often with an adjective or past participle, like “keep calm” or “keep the door closed.” “Kept” is used when that maintained condition was true in the past or in perfect or passive structures. This meaning emphasizes control and stability.

“Keep” appears in several common structures that determine whether you use “keep” or “kept” based on tense and auxiliaries. Learning these patterns helps you choose the correct form automatically. The verb form changes, but the structure stays the same.

Rule	Example
Keep + noun	Keep the change.
Keep + adjective	Keep quiet.
Keep + noun + adjective	Keep the room clean.
Keep + -ing	Keep trying.
Have or has + kept	I have kept your secret.
Be + kept	The documents are kept here.