🔍 Passive Voice Checker
By ToolNimba Editorial Team · Updated 2026-06-20
This is a heuristic, not a grammar engine. It flags a "to be" verb followed by a likely past participle, so it may miss some passives and occasionally flag an active sentence. Treat the highlights as prompts to review, not hard rules.
This passive voice checker scans your writing and highlights sentences that look passive, so you can decide where a stronger active version would read better. It counts the passive hits and shows your passive ratio at a glance, and it runs entirely in your browser, so your text is never uploaded. Remember that it is a heuristic, meaning it flags likely passives rather than guaranteeing every one.
What is the Passive Voice Checker?
Passive voice happens when the subject of a sentence receives the action instead of doing it. In the active sentence "The committee wrote the report", the committee is doing the writing. Flip it to "The report was written by the committee" and the report, the thing being acted on, becomes the subject. The classic structure is a form of the verb "to be" (is, are, was, were, be, been, being) followed by a past participle (written, reviewed, made). That pattern is exactly what this tool looks for.
There is nothing grammatically wrong with the passive. It is the right choice when the doer is unknown, unimportant, or deliberately hidden ("The window was broken overnight"), and it is standard in scientific and legal writing. The trouble is that overusing it makes prose feel vague, wordy, and evasive. Active sentences are usually shorter and clearer because they name who did what. Most style guides therefore suggest keeping the passive for the cases that genuinely need it and rewriting the rest.
Because this checker is a heuristic, it does not parse grammar the way a human does. It finds a "to be" verb sitting next to a likely past participle and flags that span, allowing for a single adverb in between (as in "was quickly approved"). It treats any word ending in -ed as a possible participle and keeps a list of common irregular ones such as "written", "taken", and "made". This keeps the tool fast and completely private, but it means two things: it can miss a passive built on an unusual irregular verb, and it can occasionally flag an active sentence where "is" happens to sit beside an -ed adjective.
The practical workflow is simple. Run your draft through the checker, look at the highlighted spans, and ask of each one: do I know or care who is doing the action, and would naming them make the sentence clearer? If yes, rewrite it in the active voice. If the passive is doing real work, leave it. The passive ratio at the top gives you a quick health check; many editors aim to keep passive sentences well under a quarter of the total in general writing.
When to use it
- Tightening a blog post or essay before publishing by finding and rewriting weak passive sentences.
- Helping students learn to spot passive constructions and practise converting them to active voice.
- Reviewing business emails and reports so the writing names who is responsible instead of hiding it.
- Editing fiction or copywriting where active, direct sentences keep the reader engaged.
How to use the Passive Voice Checker
- Paste or type your text into the input box. A sample loads so you can see how it works.
- Click Check passive voice, or just keep typing, to highlight likely passive spans in amber.
- Read the stats: total sentences, passive hits, passive sentences, and your passive ratio.
- Rewrite the highlighted sentences in active voice where it helps, then copy the report if you need a record.
Formula & method
Worked examples
You paste the sentence "The results were reviewed by the panel."
- The checker finds "were", a form of "to be".
- The next word "reviewed" ends in -ed, so it counts as a past participle.
- The span "were reviewed" is highlighted as a passive hit and the sentence is marked passive.
Result: Flagged passive. Active rewrite: "The panel reviewed the results."
You paste "The new policy is being enforced by managers."
- The checker sees "is" followed shortly by "being", both forms of "to be".
- It finds "enforced", an -ed past participle, right after.
- The passive construction "is being enforced" is highlighted and counted.
Result: Flagged passive. Active rewrite: "Managers are enforcing the new policy."
Common passive sentences and their active rewrites
| Passive (flagged) | Active rewrite | Why active is clearer |
|---|---|---|
| Mistakes were made. | The team made mistakes. | Names who is responsible. |
| The cake was eaten by the dog. | The dog ate the cake. | Shorter and more direct. |
| A decision will be reached. | The board will reach a decision. | Identifies the actor. |
| The bug was fixed last night. | We fixed the bug last night. | Adds accountability. |
| The form must be signed. | You must sign the form. | Tells the reader what to do. |
The "to be" verbs the checker watches for
| Tense or form | Words |
|---|---|
| Present | is, are |
| Past | was, were |
| Base and infinitive | be |
| Past participle and gerund | been, being |
Common mistakes to avoid
- Treating every flag as an error. Passive voice is not wrong, it is a choice. When the doer is unknown or unimportant, the passive is the better option. Use the highlights as a prompt to review, not a command to rewrite everything.
- Assuming any "was" plus -ed word is passive. Some -ed words are adjectives, not participles, as in "She was tired" or "He was interested". The heuristic may flag these, so read the sentence and judge whether an action is really being received.
- Confusing past tense with passive voice. "The dog ran fast" is past tense but fully active. Passive voice needs a "to be" verb plus a past participle, not just a verb in the past. Past tense alone is never the problem.
- Expecting the tool to catch every passive. Because it relies on patterns, the checker can miss passives that use rare irregular participles or unusual phrasing. Treat a clean result as encouraging, not as proof that no passive voice remains.
Glossary
- Passive voice
- A sentence structure where the subject receives the action, formed with a "to be" verb plus a past participle, as in "The report was written".
- Active voice
- A sentence structure where the subject performs the action, as in "She wrote the report". It is usually shorter and clearer.
- Past participle
- The verb form used in passives and perfect tenses, such as "written", "taken", or "reviewed". Regular ones end in -ed.
- Auxiliary verb
- A helper verb. In the passive, the helper is a form of "to be" (is, are, was, were, be, been, being) that pairs with the participle.
- Passive ratio
- The share of sentences flagged as passive, shown as a percentage. A lower ratio generally means more direct, active writing.
- Heuristic
- A rule-of-thumb method that gives a fast, useful answer without being perfect. This checker uses patterns rather than full grammar parsing.
Frequently asked questions
What is a passive voice checker?
A passive voice checker is a tool that scans your text and highlights sentences that appear to be in the passive voice. This one looks for a "to be" verb followed by a past participle, counts the matches, and shows your passive ratio so you can decide where to rewrite.
How does this tool detect passive voice?
It uses a heuristic. It searches for "to be" verbs such as is, are, was, were, be, been, and being, then checks whether a past participle follows, allowing one optional adverb in between. Past participles are matched from a list of common irregular verbs plus any word ending in -ed.
Is passive voice always bad?
No. Passive voice is a legitimate tool. It is useful when the doer is unknown, irrelevant, or deliberately not named, and it is standard in scientific and legal writing. The goal is to use it on purpose rather than by accident, which is why the checker only highlights rather than deletes.
Why did it flag a sentence that is not passive?
Because it matches patterns instead of fully parsing grammar, it can flag a "to be" verb next to an -ed adjective, as in "She was excited". Read each highlight and keep it only if an action is genuinely being received by the subject.
Can it miss some passive sentences?
Yes. The checker may miss passives built on uncommon irregular participles or unusual phrasing, since it relies on a finite list and the -ed pattern. A clean result is a good sign but not a guarantee, so a final human read is always wise.
Is my text sent to a server?
No. All analysis runs locally in your browser with plain JavaScript. Your writing is never uploaded, stored, or shared, so the tool is safe to use with drafts, private documents, and sensitive material.