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Active Voice and Passive Voice Explained

One of the most consistent pieces of writing advice is “prefer active voice.” But what does that actually mean? Understanding the structural difference between active and passive constructions, and knowing when each serves the reader, will sharpen your writing across essays, emails, and every other genre.

What Is Voice?

In grammar, voice describes the relationship between the verb and the subject of a sentence: specifically, whether the subject is performing the action or receiving it. There are two voices in English: active and passive.

Voice is a feature of transitive verbs — verbs that take a direct object. Intransitive verbs (verbs with no object, like “arrive” or “sleep”) cannot be made passive.

Active Voice

In an active voice sentence, the grammatical subject is the agent — the entity doing the action. The structure is:

Subject (doer) → Verb → Object (receiver)

Examples:

• The council approved the budget. (Council is the agent; budget receives the action.)
• Shakespeare wrote Hamlet. (Shakespeare is the agent; Hamlet receives the action.)
• The dog chased the cat. (Dog acts; cat is acted upon.)

Active sentences are direct, concrete, and usually shorter. It is immediately clear who is responsible for the action.

Passive Voice

In a passive voice sentence, the grammatical subject receives the action rather than performing it. The agent is demoted to an optional prepositional phrase (“by ...”) or omitted entirely.

Structure: Subject (receiver) → to be + past participle → [by agent (optional)]

Examples:

• The budget was approved by the council. (Budget is now the subject but still receives the action.)
• Hamlet was written by Shakespeare.
• The cat was chased by the dog.
• Mistakes were made. (Agent omitted entirely.)

The hallmark of the passive is the combination of a form of to be (is, was, were, has been, will be, etc.) with a past participle (written, approved, chased, made).

How to Convert Between Active and Passive

To change active to passive:

1. Move the object of the active sentence to the subject position.
2. Change the verb to “to be + past participle.” Match the tense of the original verb.
3. Optionally add the original subject as a “by” phrase.

Active: “The engineer designed the bridge.”
Passive: “The bridge was designed by the engineer.”

To change passive to active:

1. Find the agent (the “by” phrase, or infer it if missing).
2. Move it to the subject position.
3. Change the verb to its active form in the same tense.
4. Move the original subject to the object position.

Why Prefer Active Voice?

Active voice is usually recommended for several reasons rooted in clarity and efficiency:

• Clearer responsibility: Active sentences make it obvious who does what. Passive sentences can obscure agency, whether intentionally or not. “The data was mishandled” hides who mishandled it; “The lab assistant mishandled the data” does not.
• Shorter sentences: Passive constructions typically add words. “The bill was passed by Parliament” uses seven words; “Parliament passed the bill” uses four.
• Stronger verbs: Active voice puts the action verb in a prominent position. Passive voice buries it between “was” and “by,” weakening its impact.
• Reader engagement: Active prose is more dynamic and easier to follow. Readers connect more readily with an agent doing something than with a thing having something done to it.

When Passive Voice Is Appropriate

Passive voice is not a grammatical error; it is a stylistic choice that is sometimes the better one:

• The agent is unknown or irrelevant: “The window was broken.” You may not know (or care) who broke it.
• Scientific writing: Passive is traditional in lab reports and scientific papers to foreground the procedure over the researcher. “The solution was heated to 80°C” is conventional in this context.
• Emphasising the receiver: When what was done to something matters more than who did it, passive serves better. “The president was assassinated in 1963” rightly puts Kennedy at the centre of the sentence.
• Avoiding repetition: If the agent has just been named and repeating the name would be awkward, passive can vary sentence structure naturally.
• Deliberate vagueness: Passive is used in politics and diplomacy to dodge attribution: “It was decided that the project would be cancelled.” Good writers use this strategically; avoid it when clarity is what you owe your reader.

Common Passive Traps in Academic Writing

Students often slip into passive voice when trying to sound formal or objective, producing sentences like “It can be seen that the results suggest...” or “It should be noted that...” These are wordy and weak. “The results suggest...” or a simple “Note that...” is tighter and just as formal. Passive is not the same as academic register; careful, precise active sentences are the actual mark of strong academic writing.

Summary

In active voice, the subject performs the action (Subject → Verb → Object). In passive voice, the subject receives it (Subject → be + past participle → optional by-phrase). The passive is formed with a form of “to be” plus a past participle and can always be identified by the “by zombies” test. Active voice is generally preferred because it is shorter, clearer about responsibility, and more direct; passive voice is appropriate when the agent is unknown, irrelevant, or deliberately omitted, and in scientific and formal writing where convention demands it. Mastering both allows you to choose deliberately rather than default.