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Free AI checker for ChatGPT, Gemini, Claude, DeepSeek and polished drafts

Free AI Detector, AI Checker & 100+ AI Tools

FiftyGPT's free AI detector shows whether text is human-written, AI-generated, mixed, or paraphrased — paste yours for clear sentence-level signals in seconds.

FiftyGPT is a free suite of 100+ AI tools for students — AI detection, writing, paraphrasing, citations, summarizing, grammar, and study help.

AI Detector

Estimate how likely a text was written by AI, with sentence-level signals and clear explanations.

0 characters Free fair-use limit: 100 runs/day
Privacy-aware checks Sentence-level clues Fast online review
Next steps

Move from detection to a complete writing review

Most visitors start with the AI detector, then use one focused tool for the next job.

Popular tools

Useful AI tools, one click away

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Toolkit

Browse the writing, study, image, and utility toolkit

105 free tools are organized for fast discovery, internal linking, and search-friendly topical coverage.

AI Detector

Estimate how likely a text was written by AI, with sentence-level signals and clear explanations.

AI Humanizer

Rewrite stiff, robotic-sounding text into natural, readable language while keeping the meaning.

AI Paraphraser

Rephrase sentences and paragraphs while preserving the original meaning.

AI Summarizer

Condense long articles, papers, and documents into clear summaries.

Grammar & Spell Checker

Find and fix grammar, spelling, and punctuation issues with suggestions.

AI Translator

Translate text between major world languages with natural phrasing.

Plagiarism Checker

Check text for duplicated content. Requires a plagiarism data provider connected in admin.

Word Counter

Count words, characters, sentences and paragraphs with reading and speaking time. Works instantly, no API needed.

AI Chat

Chat with an AI assistant for questions, ideas, and writing help.

AI Math Solver

Step-by-step math solutions that teach the method, not just the answer.

AI Quiz Generator

Turn class notes into multiple-choice practice questions with an answer key.

Essay Outline Generator

Create a clear essay structure with thesis, introduction, body sections, counterargument, and conclusion.

Study Schedule Generator

Build a day-by-day study plan from your exam topic and timeline.

GPA Calculator

Estimate semester GPA from course credits and letter grades using a common 4.0 scale.

Final Grade Calculator

Calculate the final exam score needed to reach a target course grade.

AI Student CV Builder

Create a clean student CV draft for internships, part-time jobs, graduate schemes, and campus roles.

Internship Cover Letter Generator

Draft a focused cover letter for internships, placements, student jobs, and early-career applications.

Erasmus Motivation Letter Generator

Plan a persuasive Erasmus or exchange motivation letter with academic goals and cultural fit.

Personal Statement Planner

Turn course interests and evidence into a clear personal statement plan.

Study Abroad Checklist Generator

Create a timeline checklist for study abroad paperwork, housing, money, health, and arrival tasks.

Student Visa Document Checklist

Organize student visa documents, financial proof, admission evidence, housing, and appointment tasks.

UCAS Personal Statement Planner

Plan a UK UCAS personal statement around course motivation, super-curricular evidence, and reflection.

ECTS Credit Calculator

Add ECTS credits and estimate weighted averages from course lines.

ECTS Grade Converter

Convert a numeric score into an approximate ECTS A to F grade band.

Student Budget Planner

Estimate monthly student income, expenses, leftover money, savings, and buffer.

Lecture Notes Summarizer

Summarize lecture notes into key points, terms, and revision actions without an external API.

AI Flashcard Maker for Students

Create CSV flashcards from notes, terms, lecture summaries, and textbook points.

Thesis Proposal Outline Generator

Build a supervisor-ready thesis proposal outline with question, gap, method, and contribution.

Research Gap Finder

Identify possible literature gaps from source notes, topic summaries, and dissertation ideas.

Exam Revision Timetable Generator

Create a day-by-day revision timetable from exam timing, topics, weak areas, and practice needs.

Readability Checker

Check reading ease, grade level, sentence length, and clarity signals without an AI API.

Weighted Grade Planner

Calculate a weighted course grade from assignments, scores, and category weights.

Browse all 105 tools

Categories

Explore the full toolkit by category

AI detection leads the way, backed by writing, academic, business, utility, and image tools — organized so every domain is easy to find.

AI detector guide

How the AI checker works and when to trust it

Built for search intent, answer engines, and real users who need more than a blank text box.

AI Detector estimates how likely a piece of text was written by AI. It analyzes your text sentence by sentence, highlighting patterns that are more common in AI-generated writing and giving you a plain-English explanation for each signal. The result is a probability estimate, not a verdict.

What does AI Detector do?

AI Detector scans your text for statistical and stylistic clues that often appear in machine-generated writing. It looks at things like sentence length variation, word predictability, repetition, and unusual phrasing. Then it shows you which sentences look most suspicious and why. You get a percentage estimate and a breakdown you can actually read. This helps you decide whether to trust a piece of text or dig deeper.

How do you use AI Detector?

Using AI Detector is straightforward. Follow these steps:

  1. Copy the text you want to check. It can be an essay, an email, a blog post, or a social media caption.
  2. Paste it into the input box labeled "Paste your text."
  3. Click the "Detect AI" button.
  4. Wait a moment while the tool analyzes your text.
  5. Review the results. You'll see an overall likelihood score and sentence-level highlights.
  6. Read the explanations for each flagged sentence to understand what triggered the signal.

That's it. No account needed, and your text isn't stored.

When should you use AI Detector?

There are several situations where AI Detector can be helpful:

  • Teachers and professors reviewing student submissions. You can get a second opinion before having a conversation with a student.
  • Writers and editors checking drafts. If you use AI to generate ideas or outlines, you can see whether the final text still reads as human-written.
  • Marketers and content managers reviewing guest posts or freelance articles. It helps you spot content that might be low-effort or auto-generated.
  • Students who want to check their own work before submitting. If you wrote everything yourself, the tool should show a low AI likelihood.
  • Anyone who receives a suspicious email or message and wants to know if it was written by a bot.

Keep in mind that AI Detector is a tool for gathering evidence, not for making final judgments. Use it alongside your own reading and judgment.

What are the limits of AI Detector?

No AI detector is perfect. Here's what you should know:

  • False positives happen. Human writing can sometimes look like AI writing, especially if it's very formal, repetitive, or uses common phrases. A high score doesn't prove a text was AI-generated.
  • False negatives happen too. AI writing can be edited to sound more human, and the tool might miss it. A low score doesn't guarantee the text is human-written.
  • Short texts are less reliable. If you paste only a few sentences, the estimate is based on limited data. Longer samples give better results.
  • Non-native English writing can sometimes trigger false positives because of unusual phrasing or simpler sentence structures.
  • The tool doesn't know the source. It can't tell you which AI wrote the text or whether it was paraphrased.

Use AI Detector as one piece of evidence. Combine it with your own reading, context, and other checks. If you're a teacher, don't accuse a student based solely on this tool's output. If you're a writer, don't assume your human-written text is safe just because the score is low.

AI Detector is free to use and designed to be transparent. It shows you why it flagged something, so you can decide what to do next. Try it on a sample of your own writing to see how it works.

Why us

Responsible AI checking for real workflows

Honest results

Confidence levels and explanations for AI writing signals.

Fast and free

Free core tools with generous limits, quick on any device.

Private by design

We log counts, not content. Your text stays yours.

English-first, international-ready

Written for U.S. English users and useful for Canada, the U.K., Australia, and global English workflows.

API ready

Integrate any tool with a simple REST API.

Always improving

New tools and upgrades ship regularly.

The future of writing

AI tools that support judgment instead of replacing it

Analyze, improve, and create content faster while keeping your own voice. Built for students, writers, marketers, developers, and teams.

105+Free AI tools
50+Languages supported
100%Transparent caveats
24/7Always available
Workflow

How it works

1

Paste at least 30 words

Use an essay, article, email, application draft, or content brief with enough text to show patterns.

2

Review the AI probability

Read the score, confidence, explanation, and the strongest AI-like sentence signals.

3

Use the right next tool

Humanize tone, paraphrase wording, check grammar, verify originality, or browse the full toolkit.

FAQ

Frequently asked questions

How accurate is the AI detector?
Accuracy varies with text length and editing. Longer, unedited texts give the most reliable signals. Every result includes a confidence level, and results should be treated as estimates, not proof.
Can it detect ChatGPT, Claude and Gemini text?
It analyzes general statistical patterns common to AI-generated text rather than fingerprinting one specific model, so it works across modern AI writing tools.
Why did my own writing score as AI?
Very formal, structured writing — and especially text already polished by grammar tools — can resemble AI patterns. This is exactly why scores alone should never be used to accuse anyone.
What is the best free AI detector workflow?
The best workflow is to check a complete draft, read the probability and explanation, review flagged sections, then verify with drafts, sources, citations, and human judgment.
Can this AI checker detect ChatGPT, Gemini, Claude, and DeepSeek?
It reviews writing patterns common to AI-generated text from many models, including ChatGPT-style systems, Gemini, Claude, and DeepSeek. It estimates likelihood; it does not prove a specific model wrote the text.
Should I use competitor brand keywords on this detector page?
No. Competitor brand searches should be handled in honest comparison articles. The detector page should focus on task keywords such as AI detector, AI checker, ChatGPT detector, and AI text detector.
How does the AI Detector work?
It analyzes writing patterns — sentence structure, predictability, and phrasing — using a language model to estimate the probability that a text was AI-generated. Results are probabilistic estimates, not absolute proof.
Is AI detection 100% accurate?
No detector is 100% accurate. Treat results as one signal among many: short texts, edited AI text, and formal human writing can all affect scores. We always show a confidence level and never present estimates as fact.
Is my text stored or shared?
Tool inputs are processed to generate your result and are not published anywhere. Usage statistics store counts only, not your text. See our Privacy Policy for details.
Which languages are supported?
The writing tools work in most major languages, including English, Spanish, French, German, Arabic, Urdu, Hindi and Chinese.
Can I integrate these tools into my own product?
Yes — an API is available. See the API page or contact us for access and volume pricing.
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