“Free AI detector” can mean different things
Before choosing a free detector, separate the amount accepted in one check, the total allowance and the reset rule. A 1,200-word input cap, 10,000 words per month and a one-time word balance answer different questions. Also check whether the specific free workflow needs an account.
Free detector access published by selected providers
These pages were rechecked on 2 November 2026. Published offers can change, and a public page is not a test of what a particular account will receive. Confirm the limits shown in the product before relying on them.
Scroll the table to compare all columns.
| Tool | Published free access | Account information in the cited source | Boundary to check |
|---|---|---|---|
| GPTZero | Its student page advertises up to 10,000 words per month and a Chrome extension | Its help page says a free dashboard account is needed for longer texts or batches | The monthly allowance does not establish the maximum accepted in one check or every no-account condition |
| Paperpal | Its detector page lists 5 scans/day, up to 1,200 words each | Login/signup links are present; the page does not settle every free-check account condition | A daily scan count and a per-scan cap both apply to the published offer |
| WriteHuman | Its detector page advertises free daily scans | It explicitly says no account is required for those daily scans | The free offer does not state a numeric daily scan count or a free per-input cap |
| Scribbr | Its detector page advertises unlimited free checks, up to 1,200 words per submission | It explicitly says no sign-up is required | Unlimited checks does not remove the per-submission cap or establish complete accuracy |
| Sapling | Its public checker says a free check covers the first 2,000 characters; Pro supports up to 100,000 characters | The cited page does not specify every free allowance/account condition | Characters are not words; do not assume a long uploaded document was checked in full |
| HumanWords | A free account includes a one-time 300-word allowance shared across AI checks and humanizing, as set out in the Terms | The allowance is once per account and requires that account | The separate no-account homepage preview humanizes an opening; it is not a no-account AI detector scan |
This table compares access, not which detector is better. Provider statements about accuracy, guaranteed authorship or safety were not adopted as our test results. For broader product/report fit, use our GPTZero alternatives guide.
Read the unit and reset together
A free offer is easier to interpret when you write its conditions in separate fields:
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| Kind of limit | What it answers | What it does not establish |
|---|---|---|
| Per-check words or characters | How much text a particular check accepts or covers | How many checks you can run or how much refreshes later |
| Scans per day | How many scans the published daily offer includes | That every scan accepts an unlimited-length document |
| Monthly words | A plan's stated word allowance for the period | The per-input cap, account rules or treatment of reruns |
| One-time shared balance | A balance available once across the named activities | A fresh balance for each activity or a monthly refill |
| Unstated numeric allowance | A detail the public offer leaves unresolved | That the service is unlimited |
For example, GPTZero's student offer describes a monthly word allowance, while Sapling's free-check notice describes a character span. Treating those figures as if they were the same kind of quota would hide an important difference (GPTZero: free student offer; Sapling: check coverage).
If you need to know when a counter resets or whether a rerun consumes allowance, find the applicable plan/help information or ask the provider. Do not fill an unstated rule with a guess.
Plan a check of a longer draft
Suppose an invented 2,400-word draft must fit a 1,200-word per-submission cap. Two equal parts would each meet that size cap. That is arithmetic, not a live test, a promise that every text type is eligible or a method for turning two scores into a whole-document result.
If you are using the cited Paperpal offer, also check its published daily scan count. If you are using the cited Scribbr offer, note that “unlimited checks” still retains its per-submission limit. Verify the current product conditions rather than assuming the word “free” settles the whole task (Paperpal: free tier; Scribbr: free checks).
A shortened or split passage also changes the context sent to a detector. Record exactly what was checked and avoid presenting an excerpt's result as a score for an entire essay. Do not simply average percentages whose meanings or inputs differ. Our score-interpretation guide explains that limitation.
Understand a shared allowance before using it twice
HumanWords' Terms say its Free plan has 300 input words once per account, shared by AI checks and humanizing. Each successful request counts its input words, including requested reruns; failed processing does not consume allowance (HumanWords: plans and allowance).
For an original planning example:
- Start with 300 available words.
- A successful check that counts 180 input words would leave 120.
- Humanizing the same 180-word passage would need another 180 words of allowance; the remaining 120 would not cover it.
This is not a report of a real account or a processing test. It shows why one shared balance is different from separate free balances for checking and rewriting. Read the actual account balance and current terms; do not assume the same rule applies to another provider.
The homepage preview is a separate opening humanization experience. It does not turn the account allowance into a free monthly quota or provide an anonymous AI check. Follow the published allowance rules rather than creating accounts to reset them.
Before you paste a draft
Use this original pre-check worksheet to decide whether an offer fits the job:
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| Record | What to confirm |
|---|---|
| Task | An AI-writing estimate, a school report, a plagiarism check or a rewrite are different jobs |
| Exact input | Language, text type, word/character count and portion you intend to submit |
| Free conditions | Per-input cap, total allowance, reset rule, account and any trial conditions |
| Data handling | Applicable storage, reuse, retention, deletion and report-sharing terms |
| Permission | School, employer, research and source-material restrictions |
| Result review | What the score means and which human checks remain necessary |
A familiar upload box or a “free” label does not answer the data-handling questions. Before sending private or unpublished material, read the applicable policy and the rules governing that writing. Our essay-upload privacy checklist explains what to ask; consult the HumanWords Privacy Policy for our own practices.
Read the fine print before the score.
- 1 · CoverageInput limit
How much of your passage will the service actually check?
- 2 · AccessAccount rules
Do you need to sign in or start a trial?
- 3 · AllowanceFree-use limit
Does the allowance reset, expire or run out once?
- 4 · Your writingPrivacy terms
What happens to the text after you submit it?
Free access does not establish accuracy or permission
An AI-writing result is a model estimate, not a record naming the author. Turnitin's guidance cautions that its report can misidentify human or AI text and should not be the sole basis for adverse action (Turnitin: report limitations). That warning does not rank the free tools above; we ran no common accuracy test.
If a result raises a question, review the writing and source evidence instead of revising solely to move the number. Keep drafts and notes, and ask how an institutional report will be reviewed. If revision assistance is permitted and you choose HumanWords, inspect retained changes yourself and check current plans before relying on an allowance.
Sources and scope
- GPTZero: student offer and usage help. Published monthly offer and longer-text/batch account guidance; checked 2 November 2026.
- Paperpal: AI detector. Its own free-tier row, not its claims about competitors' quality; checked 2 November 2026.
- WriteHuman: AI detector. Daily no-account offer; a numeric free counter/cap is not stated in that offer; checked 2 November 2026.
- Scribbr: AI detector. Unlimited-check and 1,200-word submission/no-signup statements; checked 2 November 2026. Privacy and accuracy marketing were not independently tested.
- Sapling: AI detector. First-2,000-character coverage and Pro cap; checked 2 November 2026.
- HumanWords: Terms and shared word allowance, plans and homepage. One-time shared account allowance and separate preview; checked 2 November 2026.
- Turnitin: AI Writing Report. Model-estimate and human-review cautions; checked 2 November 2026.