Active vs passive voice: how to spot it and when to use each
The advice to "avoid the passive" is repeated so often that many writers treat it as a grammar rule. It is not. The passive is correct, and sometimes it is the right call. This guide gives you a reliable test for spotting it and clear cases for when each voice serves you best.
Voice describes the relationship between the verb and the thing doing the action. In an active sentence, the subject does the verb: "The committee approved the budget." In a passive sentence, the subject receives the verb: "The budget was approved by the committee." Both are grammatical. Both can be clear. The choice changes where the reader's attention lands and how direct the sentence feels.
How to spot passive voice
The passive has a fixed grammatical recipe: a form of the verb "to be" (is, are, was, were, be, been, being) followed by a past participle (the form of the verb that usually ends in -ed or, for irregular verbs, takes a form like written, given, taken). "Was approved", "is reviewed", "are produced", "has been signed". Once you know the recipe, the passive is easy to find.
The most reliable shortcut is the zombie test, popularised by the writer Rebecca Johnson. After the main verb, try inserting the phrase "by zombies". If the sentence still works grammatically, it is passive. "The report was written by zombies" works, so "was written" is passive. "The intern wrote the report by zombies" does not work, so "wrote" is active. The test catches the cases people miss, including passives where the doer has been dropped entirely: "Mistakes were made" passes the zombie test ("Mistakes were made by zombies"), which is exactly why politicians reach for it.
Why so much advice warns against it
The passive earns its bad reputation in three ways. It can hide who did something, which is useful for dodging responsibility and terrible for clear communication. It adds words: "was approved by the committee" is three words longer than "the committee approved". And stacked up across a paragraph, it drains energy from prose, turning lively reporting into a flat recital of things that happened to things.
George Orwell's 1946 essay "Politics and the English Language" singled out the passive as a tool of vague, evasive writing, and the style guides followed. The warning is sound as far as it goes. The mistake is treating a useful caution as an absolute ban, because plenty of good sentences are passive on purpose.
When the passive is the right choice
Use the passive when the doer is unknown. "My bike was stolen last night" is better than inventing an active subject you do not have. Use it when the doer is irrelevant or obvious: "The suspect was arrested" keeps the focus on the suspect, and everyone knows the police did the arresting. Use it when the thing acted upon is the real subject of your paragraph: if you are writing about a building, "The cathedral was completed in 1265" rightly keeps the cathedral in the subject slot rather than shoving in the masons.
Scientific and technical writing leans on the passive for a reason. "The samples were heated to 200 degrees" puts the method first, which is what a replicating researcher cares about; who held the beaker is beside the point. Many journals still prefer this convention, though some now encourage the active "we heated the samples" for readability. Check the style guide for your field rather than applying a blanket rule.
Converting passive to active
To turn a passive sentence active, find the doer (the noun after "by", or the one implied) and move it to the front as the subject. Then change the verb from the "to be" plus participle form to a simple active verb.
Passive: "The decision was made by the board after the figures were reviewed by the auditors." Active: "The board made the decision after the auditors reviewed the figures." The active version is shorter, the sequence of who did what is clear, and it reads with more momentum.
Passive: "It was decided that the launch would be delayed." This one has no doer at all, which is the tell. Active: "The product team decided to delay the launch." You have to supply the missing subject, and that is the point; forcing yourself to name the doer is how the active voice keeps writing honest.
Converting active to passive on purpose
The reverse move is legitimate when it improves focus. Active: "An earthquake destroyed the old harbour wall in 1783." If your paragraph is about the harbour wall, the passive keeps it in the subject position: "The old harbour wall was destroyed by an earthquake in 1783." Now the sentence opens on the subject the reader is tracking, and the cause arrives as new information at the end, where new information belongs.
This is the deeper principle. Sentences read best when they open with old or familiar information and close with the new. Sometimes the active voice delivers that order, and sometimes the passive does. Picking the voice that puts the known thing first is a more useful habit than mechanically preferring one voice everywhere.
A quick self-edit pass
When you revise, do not hunt down every passive and convert it. Instead, find the passives where the doer has vanished and ask whether the reader deserves to know who acted. "The funding was cut" invites the question "by whom?", and answering it usually sharpens the sentence. Leave the passives that genuinely keep the right subject in focus.
A grammar tool can flag passive constructions for you so you decide consciously rather than by accident. The point is not zero passives; it is zero accidental passives. Every passive in a polished draft should be one you chose.
What to do next
Paste a draft into the Phrasit grammar checker to flag passive constructions so you can decide which to keep and which to convert. Then run the prose through the reading level analyzer to check that the rewrite reads as cleanly as you hoped, since cutting accidental passives usually drops the sentence length and the grade level together.