Sprawdzanie Gramatyki — Darmowe narzędzie online

Grammar Checker: Free Grammarly Alternative That Runs in Your Browser

Good writing is clear writing. Whether you are crafting a business email, writing a blog post, submitting a college essay, or composing a social media caption, grammar mistakes undermine your credibility and distract from your message. This grammar checker runs entirely in your browser, analyzing your text against 30+ rules for grammar, spelling, and style without ever sending your words to a server.

What This Grammar Checker Detects

Our rule-based engine checks for the most common and impactful writing errors across three categories.

Grammar Errors (Red Highlights)

Double words are one of the most common typos — "the the", "is is", "to to". Your brain autocorrects these when reading, which is why they slip through manual proofreading. We also check for capitalization errors after sentence-ending punctuation (periods, exclamation marks, question marks). Additionally, we detect common word confusions: their/there/they're, your/you're, its/it's, affect/effect, then/than, loose/lose, accept/except, complement/compliment, principal/principle, stationary/stationery, and more.

Spelling Errors (Blue Highlights)

We check for 20+ of the most commonly misspelled English words: accommodate, achievement, apparently, beginning, believe, business, calendar, colleague, committee, conscience, definitely, disappear, environment, exaggerate, February, foreign, government, guarantee, immediately, independent, knowledge, maintenance, necessary, occasion, occurrence, possession, privilege, recommend, referred, relevant, separate, successful, and tomorrow. These words trip up even experienced writers because their spelling defies intuitive phonetic rules.

Style Suggestions (Yellow Highlights)

Passive voice detection identifies sentences where the subject receives the action rather than performing it ("The report was written by the team" vs. "The team wrote the report"). While passive voice is sometimes appropriate, overuse weakens writing. Run-on sentence detection flags sentences exceeding 40 words, which are typically hard to follow and should be split. We also flag overuse of weak qualifiers and filler phrases.

Understanding Readability Scores

The Flesch Reading Ease score is the most widely used readability metric, calculated from average sentence length and average syllable count per word. Scores range from 0 (extremely difficult) to 100 (extremely easy). Most popular online content targets a score of 60-70, equivalent to 8th-9th grade reading level. Academic and technical writing typically falls in the 30-50 range. The Flesch-Kincaid Grade Level translates the same formula into a US school grade level, making it easier to match your writing to your audience.

Tips for Better Writing

Beyond fixing errors, consider these evidence-based writing principles. Use short sentences. Research shows comprehension drops sharply for sentences over 25 words. Mix short and medium sentences for rhythm. Choose simple words. "Use" beats "utilize." "Help" beats "facilitate." Write in active voice. Active sentences are shorter, clearer, and more engaging. Read aloud. If you stumble reading your own text, your readers will too. These principles, combined with error-free grammar, produce writing that is clear, credible, and compelling.

Why Client-Side Grammar Checking Matters

Most grammar checkers — Grammarly, ProWritingAid, Hemingway — require sending your text to external servers. For personal journals, business documents, legal correspondence, or student work, this raises legitimate privacy concerns. Our tool processes everything locally in your browser using JavaScript pattern matching. Nie server calls, no data collection, no account required. Your text stays on your device.