Passive Voice Detector: Write More Direct Prose Online (2026)

In writing, voice describes the relationship between the action of a sentence and the subject performing that action.

While passive voice is grammatically correct, overusing it can make your writing feel wordy, flat, and detached. Most editors and professional writing guidelines recommend using the active voice because it makes your copy more direct, concise, and engaging.

To help you audit your sentences and highlight passive voice constructions, FluxToolkit provides a free, client-side Passive Voice Detector.

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Active vs. Passive Voice: What is the Difference?

The difference lies in who or what is performing the action in the sentence:

Active Voice

In the active voice, the subject of the sentence performs the action:

Subject (Actor) $\rightarrow$ Verb (Action) $\rightarrow$ Object (Receiver)
Example: "The developer optimized the source code."

Here, the developer (subject) is the one performing the optimization (action).

Passive Voice

In the passive voice, the subject of the sentence receives the action:

Object (Receiver) $\rightarrow$ Auxiliary Verb + Past Participle $\rightarrow$ Subject (Actor, optional)
Example: "The source code was optimized by the developer."

Here, the source code (subject receiving action) is placed first, and the actor is relegated to the end of the sentence or omitted entirely (e.g., "The source code was optimized").

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How to Spot Passive Voice Programmatically

To identify passive voice in text, the detection engine searches for a specific grammatical pattern: a helping/auxiliary verb (form of to be) followed immediately (or closely) by a past participle verb (often ending in -ed, -en, or irregular variations).

Core Auxiliary Verbs

• be, is, are, was, were, been, being, am

The Programmatic Detection Pattern

Our detector parses your text using regex structures to match these auxiliary verbs followed by past participles. While English has irregular verbs that complicate simple regex rules, the parser captures the vast majority of occurrences:

// A simplified regex approximation for passive voice detection
const auxiliaryPattern = /\b(is|are|was|were|be|been|being|am)\b\s+([a-z]+ed|known|done|seen|written|taken|given|built|made)\b/gi;

function highlightPassiveVoice(text) {
  return text.replace(auxiliaryPattern, (match) => {
    return `<span class="bg-yellow-200 text-black px-1 rounded">${match}</span>`;
  });
}

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The "Zombie Test" for Passive Voice

If you are editing your writing manually and want a simple trick to detect passive voice, use the Zombie Test:

If you can append the phrase "by zombies" to the end of a sentence after the verb and it still makes grammatical sense, the sentence is written in the passive voice.

Example 1: "The report was finished [by zombies]."

• Makes sense grammatically. $\rightarrow$ Passive Voice.

Example 2: "The manager finished the report [by zombies]."

• Does not make sense. $\rightarrow$ Active Voice.

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Step-by-Step: How to Rewrite Passive Sentences

Follow these steps to convert passive constructions to active voice:

Step 1: Input Your Text

Paste your draft into the Passive Voice Detector workspace.

Step 2: Review Highlighted Phrases

Look at the highlighted phrases and the passive voice density percentage. Try to keep your overall passive voice percentage below 10%.

Step 3: Identify the Actor

Find the person or thing performing the action. If the actor is missing (e.g., "The site sitemap was generated"), determine who or what did it (e.g., "Our tool generated the sitemap").

Step 4: Rebuild the Sentence

Move the actor to the beginning of the sentence as the subject, change the verb to its active form, and place the object at the end.

• Passive: "A clean output is produced by the generator."
• Active: "The generator produces a clean output."

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Frequently Asked Questions

Is passive voice always bad?

No. Passive voice is useful when the actor is unknown, obvious, or less important than the object receiving the action. For example, in scientific research, passive voice is standard (e.g., "The solution was heated to 100°C" is preferred over "We heated the solution"). Use passive voice intentionally rather than by default.

Does Microsoft Word or Google Docs detect passive voice?

Yes, both word processors highlight passive voice in their grammar checkers. However, they only suggest rewriting them without explaining how or calculating the overall density of passive constructions across your entire text.

Can passive voice affect my SEO rankings?

Not directly. There is no algorithmic penalty for using passive voice. However, passive voice often makes sentences longer and harder to read, which can lower your Flesch readability scores. Improving readability directly impacts user engagement and SEO.

Why do writers default to passive voice?

Writers often use passive voice to make their writing sound more formal, objective, or authoritative. In business and academic writing, it is sometimes used to avoid taking responsibility (e.g., "Mistakes were made" instead of "We made mistakes").

Does the Passive Voice Detector share my writing?

No. Our tool runs 100% on the client-side. The grammatical parsing and regex highlighting calculations are executed entirely inside your browser, ensuring your documents remain completely private.

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