“Mistakes were made” is the most famous passive sentence in politics — nobody did anything; things just happened. Passive voice is not wrong, but in instructions, essays and web copy it hides who acts, bloats sentences and drains energy. This passive voice checker scans your text sentence by sentence, flags the ones built on a be-verb plus a past participle (“was written”, “is being watched”, “were made by the team”), and reports your passive percentage so you can decide how much of it you actually want.
It is a heuristic checker, not a grammar oracle — it says so openly below. Everything runs in your browser; nothing is uploaded. ¿Lo prefieres en español? Detector de Voz Pasiva.
How the checker spots a passive
English passives are built from a small kit: a form of be (am, is, are, was, were, be, been, being), optionally an adverb, and a past participle (written, chosen, built — including a built-in list of irregular participles that do not end in -ed). This checker matches that pattern in every sentence and shows you the exact words that triggered the flag. It also notes when the sentence names the doer with a by phrase — those passives are the easiest to flip into active voice, because the actor is already in the sentence: “The report was written by Sara” → “Sara wrote the report”.
Two honest limits. First, participial adjectives can look identical to passives: “the door was open” and “she is interested in art” may be flagged even though most grammarians call them adjectives — check the flagged sentence before rewriting it. Second, unusual constructions (get-passives like “he got fired”, reduced relatives like “the car stolen last week”) can slip past a pattern matcher. Treat the percentage as a strong signal and a revision checklist, not a court verdict.
How much passive is too much?
There is no official number, but working editors use rough bands: under 10% reads crisp and direct; 10–20% is normal mixed prose; over 25% usually feels evasive or bureaucratic, especially in instructions and marketing copy. Science and legal writing legitimately run higher, because the doer is often unknown or irrelevant (“the samples were heated to 90°C”). The right target is genre-dependent — the checker’s job is to make the choice conscious instead of accidental.
Worked example
Paste this paragraph: “The new bridge was designed by a local firm. It was opened in March, and the first cars were welcomed by the mayor. Residents say the crossing has cut their commute in half.” The checker flags the first two sentences as passive (both name the doer with “by”), leaves the third active, and reports 66.7%. Rewriting the first two flips the paragraph’s energy instantly: “A local firm designed the new bridge. It opened in March…” — same facts, visible actors.
Frequently asked questions
Is passive voice a grammar error? No. It is a choice. It becomes a problem when it hides responsibility (“mistakes were made”) or buries the actor in text meant to instruct or persuade.
Why was my sentence flagged when it feels active? Most likely a participial adjective (“was open”, “is closed”) or a state description. Read the match shown next to the flag — if there is no hidden doer, leave the sentence alone.
Does it detect get-passives? Not reliably: “got promoted” lacks a be-verb, so this pattern checker may miss it. It is noted here rather than hidden.
What percentage should I aim for? For web and essay writing, most editors are happy under ~15%. Use the flag list to fix the worst offenders first — the ones with a “by” phrase are free wins.
Related tools
Versión en español: Detector de Voz Pasiva: encuentra las oraciones pasivas de tu texto · Cliché Finder · Readability Checker.
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