AI Detector Pricing: What Scanning Actually Costs
Last verified: 1 September 2026 · every number below has saved evidence · How we verify
AI detectors price in incompatible units — words, credits, per-check character caps — so sticker prices tell you almost nothing. This page normalizes what can honestly be normalized to cost per 100,000 words scanned, and says plainly where that is not possible. Every price, quota and limit below was read from the vendor's own pricing page on 1 September 2026 (US rendering, USD, tax-exclusive) and is backed by a saved screenshot and page HTML.
We compare 7 verified AI detector tools. 4 publish enough for a computed cost per 100K words; 3 do not, because they do not price on monthly volume at all. That mix is a finding about this market, not a gap in the data — and it is why the tables below are separated rather than merged into one misleading ranking.
Every tool at a glance
Sorted by cost per 100,000 words, cheapest first. Each row describes a single plan — the best-value one that tool offers — so the price, volume and cap always belong together. Tools that cannot produce a cost figure are grouped underneath with their pricing model; they are never mixed into the ranking, because a label is not a low price.
| Tool | Pricing model | Best-value plan | Included volume | Per-scan cap | $ / 100K words | Free tier | Verified |
|---|---|---|---|---|---|---|---|
| ZeroGPT | Metered volume | PRO — $13.99/mo | 4,500,000 words/month | 100,000 characters/scan | $0.31 | Yes | 1 Sept 2026 |
| Originality.ai | Metered volume | Pro — $14.95/mo | 200,000 words/month | — | $7.48 | No | 1 Sept 2026 |
| GPTZero | Metered volume | Premium — $23.99/mo | 300,000 words/month | 50,000 characters/scan | $8.00 | No | 1 Sept 2026 |
| Copyleaks | Metered volume | Pro — $99.99/mo | 250,000 words/month | — | $40.00 | No | 1 Sept 2026 |
| Verified, but no cost per 100K words can be computed — these vendors do not price on a monthly word allowance | |||||||
| Sapling | Flat rate, per check | Pro — $25.00/mo | No monthly volume published | 100,000 characters/scan | Flat rate — per-check cap | Yes | 1 Sept 2026 |
| Scribbr | Free only | No paid plan | — | — | Free | Yes | 1 Sept 2026 |
| Winston AI | Metered volume | Essential — $18.00/mo | 100,000 credits/month | 200,000 characters/scan | Unit not published — cannot normalize | Yes | 1 Sept 2026 |
Source: each vendor's own pricing page, captured 1 September 2026 (US rendering, USD, tax-exclusive) with saved screenshot and page-HTML evidence. Capture method →
Cost per 100,000 words, plan by plan
Only the 4 tools that publish both a monthly word allowance and — where credits are involved — their own words-per-credit definition can appear here. Rows are sorted by the monthly-billing figure, so the comparison is like-for-like; the yearly column is shown beside it rather than mixed into the same ranking.
| Tool | Plan | Words / month | Billed monthly | $ / 100K (monthly) | Billed yearly | $ / 100K (yearly) |
|---|---|---|---|---|---|---|
| ZeroGPT | PRO | 4,500,000 | $13.99 | $0.31 | $9.99 | $0.22 |
| ZeroGPT | MAX | 7,500,000 | $29.99 | $0.40 | $20.99 | $0.28 |
| ZeroGPT | PLUS | 5,000,000 | $22.99 | $0.46 | $16.99 | $0.34 |
| ZeroGPT | EXPERT | 15,000,000 | $69.99 | $0.47 | $49.99 | $0.33 |
| Originality.ai | Pro | 200,000 | $14.95 | $7.48 | $12.95 | $6.48 |
| GPTZero | Premium | 300,000 | $23.99 | $8.00 | $12.99 | $4.33 |
| GPTZero | Professional | 500,000 | $45.99 | $9.20 | $24.99 | $5.00 |
| Originality.ai | Enterprise | 1,500,000 | $179.00 | $11.93 | $136.58 | $9.11 |
| Copyleaks | Pro | 250,000 | $99.99 | $40.00 | $74.99 | $30.00 |
| Copyleaks | Personal | 25,000 | $16.99 | $67.96 | $13.99 | $55.96 |
Formula: plan price ÷ included words per month × 100,000, rounded to the cent. Credits are converted only with the vendor's own published ratio — Originality.ai states "1 credit equals 100 words"; Copyleaks states "1 credit covers up to 250 words or 1 image". GPTZero and ZeroGPT publish word allowances directly, so no conversion is used. Full method →
Which detector is cheapest for your volume?
Worked from the same eligible plans, choosing the cheapest plan whose own published allowance actually covers the volume — not the cheapest plan divided down. Tools without a published monthly allowance cannot answer this question and are excluded rather than guessed at.
- 50,000 words/month: ZeroGPT PRO at $13.99/month billed monthly — $0.31 per 100K words, with 4,500,000 words included. Cheapest alternative from another vendor: Originality.ai Pro at $14.95/month ($7.48 per 100K).
- 250,000 words/month: ZeroGPT PRO at $13.99/month billed monthly — $0.31 per 100K words, with 4,500,000 words included. Cheapest alternative from another vendor: GPTZero Premium at $23.99/month ($8.00 per 100K).
- 1,000,000 words/month: ZeroGPT PRO at $13.99/month billed monthly — $0.31 per 100K words, with 4,500,000 words included. Cheapest alternative from another vendor: Originality.ai Enterprise at $179.00/month ($11.93 per 100K).
One vendor's allowance is large enough to win at every volume shown, so the alternative is listed beside it — the comparison is only useful if you can see what the next option costs.
The tools that cannot be reduced to a per-word price
These are verified pricing rows with real evidence behind them. They carry no cost per 100K words because their vendors do not sell monthly word volume — not because anything is missing from our records.
Sapling
Flat rate — per-check cap
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap |
|---|---|---|---|---|
| Free | $0.00 | — | — | 2,000 characters/scan |
| Pro | $25.00 | $12.00 | — | 100,000 characters/scan |
| Enterprise | Contact sales | — | — | 100,000 characters/scan |
- Free: No monthly word or character allowance is published. The vendor states only a PER-CHECK cap, which constrains one submission and is not a monthly volume, so no $/100K figure exists for this tool. Vendor wording: "Basic writing assistance and AI detector checks up to 2,000 characters per check." Compare table: AI detector characters per check 2,000; files per AI detector batch 5; snippets 20.
- Pro: No monthly word or character allowance is published — only a PER-CHECK cap, so no $/100K figure exists. Vendor wording: "Advanced writing assistance and AI detector checks up to 100,000 characters per check", repeated beneath the cards as "Pro and Enterprise support both workflows: premium writing assistance and AI detector checks up to 100,000 characters per check." Compare table: 100,000 characters per check; 10 files per AI detector batch. The page’s "Unlimited" labels apply to snippets and premium-domain use, NOT to detector volume.
- Enterprise: No monthly volume is published; the same per-check cap as Pro applies (100,000 characters per check, 10 files per batch). Adds team controls, analytics, domain administration, bulk user provisioning, SSO/SCIM, self-hosting and custom integrations.
Scribbr
Free
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap |
|---|---|---|---|---|
| Free AI Detector | $0.00 | — | — | 1,200 words/submission |
- Free AI Detector: No monthly allowance is published and no paid plan exists to normalize, so no $/100K figure exists. The only stated cap is per submission. Vendor wording: "Unlimited free AI checks — Perform an unlimited number of AI checks for free, with a limit of up to 1,200 words per submission, ensuring all of your work is authentic." The word "unlimited" here is the vendor’s own, quoted rather than asserted by us.
Winston AI
Unit not published — cannot normalize
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap |
|---|---|---|---|---|
| Free | $0.00 | $0.00 | 2,000 credits/14-day trial | — |
| Essential | $18.00 | $10.00 | 100,000 credits/month | 200,000 characters/scan |
| Advanced | $29.00 | $16.00 | 200,000 credits/month | 200,000 characters/scan |
| Elite | $49.00 | $26.00 | 500,000 credits/month | 200,000 characters/scan |
| Enterprise and Custom Plans | Contact sales | — | — | — |
- Free: Vendor states "2,000 credits / 14 day trial". Winston publishes no definition of a credit, so this cannot be converted to words. The Compare table leaves this column’s "Characters Per Scan" and "Scans Per Hour" cells EMPTY — the paid columns’ values are not carried across to it.
- Essential: Vendor states "100,000 credits / month". NO $/100K figure is published for Winston: the vendor defines a credit nowhere on the pricing page, and the definition was searched for and not found across 3 further public Winston sources on 2026-09-01 (status required-not-found-publicly). A ratio must never be derived from plan volumes. Separate per-scan constraint: up to 200,000 characters per scan; scans per hour "unlimited" (vendor wording).
- Advanced: Vendor states "200,000 credits / month". No $/100K figure: Winston publishes no definition of a credit (required-not-found-publicly, 2026-09-01) and no ratio may be derived. Adds advanced plagiarism detection, HUMN-1+ website certification and up to 5 team members. Separate per-scan constraint: up to 200,000 characters per scan; scans per hour "unlimited".
- Elite: Vendor states "500,000 credits / month". No $/100K figure: Winston publishes no definition of a credit (required-not-found-publicly, 2026-09-01) and no ratio may be derived. Adds unlimited team members. Separate per-scan constraint: up to 200,000 characters per scan; scans per hour "unlimited".
- Enterprise and Custom Plans: Custom. The page lists enterprise-grade detection capabilities tailored to the organisation, custom integrations with existing tools and platforms, and dedicated support and implementation assistance.
Plans held out of the ranking
These belong to tools that are in the comparison, but the individual plan cannot carry a standard figure. Each is listed with the reason rather than shown as a blank.
| Tool | Plan | Price | Included | Why no $/100K |
|---|---|---|---|---|
| ZeroGPT | Free | $0 | 1,250,000 words/month | Free tier |
| ZeroGPT | EDU | $22.99/mo | 70,000,000 words/year | Annual-only allowance |
| ZeroGPT | Enterprise | Contact sales | — | Contact sales |
| GPTZero | Enterprise | Contact sales | — | Contact sales |
| Copyleaks | Enterprise | Contact sales | — | Contact sales |
| Copyleaks | Education | Contact sales | — | Contact sales |
Free tiers: what they actually allow
| Tool | Included | Per-scan cap | Terms as published |
|---|---|---|---|
| ZeroGPT | 1,250,000 words/month | 15,000 characters/scan | 1,250,000 AI Detector words per month; 15,000 characters maximum per AI detection; 0 batch files; no PDF report generation; no detection history; standard moderation restrictions apply. |
| Winston AI | 2,000 credits/14-day trial | — | 2,000 credits over a 14-day trial. Includes AI content detection, AI image and deepfake detection, document scanning, picture and handwriting (OCR) scanning, email and chat support, and HUMN-1 website certification for the 14 days. |
| Sapling | — | 2,000 characters/scan | AI detector checks up to 2,000 characters per check; 5 files per AI detector batch; 20 snippets; basic writing suggestions; use on free domains. |
| Scribbr | — | 1,200 words/submission | The vendor states unlimited free AI checks with a limit of up to 1,200 words per submission. "No sign-up required — Start detecting AI-generated content instantly with our free AI Detector, without having to create an account." The vendor also states that submissions are not stored or shared. |
A $0 tier is never ranked against paid plans — dividing zero by an allowance would put every free tier at the top of a cost table and tell you nothing useful.
Every plan, tool by tool
ZeroGPT
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Free | $0.00 | — | 1,250,000 words/month | 15,000 characters/scan | Free tier |
| PRO | $13.99 | $9.99 | 4,500,000 words/month | 100,000 characters/scan | $0.31 |
| PLUS | $22.99 | $16.99 | 5,000,000 words/month | 100,000 characters/scan | $0.46 |
| MAX | $29.99 | $20.99 | 7,500,000 words/month | 150,000 characters/scan | $0.40 |
| EXPERT | $69.99 | $49.99 | 15,000,000 words/month | 350,000 characters/scan | $0.47 |
| EDU | — | $22.99 | 70,000,000 words/year | 250,000 characters/scan | Annual-only allowance |
| Enterprise | Contact sales | — | — | — | Contact sales |
Source: ZeroGPT pricing page, captured 1 September 2026.
Originality.ai
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Pro | $14.95 | $12.95 | 200,000 words/month | — | $7.48 |
| Enterprise | $179.00 | $136.58 | 1,500,000 words/month | — | $11.93 |
Source: Originality.ai pricing page, captured 1 September 2026.
GPTZero
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Premium | $23.99 | $12.99 | 300,000 words/month | 50,000 characters/scan | $8.00 |
| Professional | $45.99 | $24.99 | 500,000 words/month | 150,000 characters/scan | $9.20 |
| Enterprise | Contact sales | — | — | — | Contact sales |
Source: GPTZero pricing page, captured 1 September 2026.
Copyleaks
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Personal | $16.99 | $13.99 | 25,000 words/month | — | $67.96 |
| Pro | $99.99 | $74.99 | 250,000 words/month | — | $40.00 |
| Enterprise | Contact sales | — | — | — | Contact sales |
| Education | Contact sales | — | — | — | Contact sales |
Source: Copyleaks pricing page, captured 1 September 2026.
Sapling
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Free | $0.00 | — | — | 2,000 characters/scan | Flat rate — per-check cap |
| Pro | $25.00 | $12.00 | — | 100,000 characters/scan | Flat rate — per-check cap |
| Enterprise | Contact sales | — | — | 100,000 characters/scan | Flat rate — per-check cap |
Source: Sapling pricing page, captured 1 September 2026.
Scribbr
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Free AI Detector | $0.00 | — | — | 1,200 words/submission | Free |
Source: Scribbr pricing page, captured 1 September 2026.
Winston AI
| Plan | Billed monthly | Billed yearly | Included | Per-scan cap | $ / 100K |
|---|---|---|---|---|---|
| Free | $0.00 | $0.00 | 2,000 credits/14-day trial | — | Free tier |
| Essential | $18.00 | $10.00 | 100,000 credits/month | 200,000 characters/scan | Unit not published — cannot normalize |
| Advanced | $29.00 | $16.00 | 200,000 credits/month | 200,000 characters/scan | Unit not published — cannot normalize |
| Elite | $49.00 | $26.00 | 500,000 credits/month | 200,000 characters/scan | Unit not published — cannot normalize |
| Enterprise and Custom Plans | Contact sales | — | — | — | Contact sales |
Source: Winston AI pricing page, captured 1 September 2026.
How this page was verified, and what it does not claim
Each vendor's pricing page was opened from a US location in USD, with the monthly and annual billing views captured separately, plus the limits tables, credit definitions, trial terms and any contact-sales surfaces. Every figure above traces to one of those saved captures. Where a vendor's own comparison table and plan card disagreed, the full-resolution capture decided it.
We compare cost, not detection accuracy. This site runs no detection tests and publishes no accuracy ranking, no scores and no verdicts about which detector is "best" — that is a research question requiring controlled evaluation we have not done. What is measured here is what these tools charge.
One vendor from the original shortlist, Turnitin, is not included above. It publishes no price on any page we captured, and our capture did not obtain evidence of how its product is actually bought — so rather than assign it a pricing model on the absence of a price, it is left out entirely until that evidence exists.
Frequently asked questions
What is the cheapest AI detector per 100,000 words?
On the plans we verified on 1 September 2026, ZeroGPT PRO is cheapest at $0.31 per 100,000 words billed monthly ($0.22 billed yearly), because it bundles a very large 4,500,000-word monthly allowance. Cost per 100K is not the whole story: the per-scan character cap, the plan features and whether you will actually use the allowance all matter, and this page shows those beside the figure.
Why do some detectors have no cost-per-100K figure?
Because they do not sell monthly word volume. Sapling charges a flat rate with a per-check character cap and publishes no monthly allowance. Scribbr has no paid detector tier at all. Winston AI publishes credits per month but no definition of what a credit is worth in words, and we will not back-derive a ratio the vendor has not stated. In each case we show the pricing model instead of a number.
What does a credit mean at each vendor?
It differs, which is exactly why sticker prices are not comparable. Originality.ai states "1 credit equals 100 words". Copyleaks states "1 credit covers up to 250 words or 1 image". GPTZero and ZeroGPT skip credits and publish word allowances directly. Winston AI publishes credit counts but no words-per-credit definition on the sources we checked.
Is there a completely free AI detector?
Yes. Scribbr publishes a free AI detector with no account required and states a limit of up to 1,200 words per submission. ZeroGPT offers a permanently free tier with 1,250,000 AI Detector words per month and a 15,000-character cap per detection, and Winston AI gives 2,000 credits over a 14-day trial. The free-tier table on this page lists the published terms for each.
Do unused credits or words roll over?
Where the vendor states a rule, we record it. Originality.ai says subscription credits expire at the end of each month and separately purchased pay-as-you-go credits expire two years from purchase. Copyleaks says your allowance resets at the start of each new billing cycle. For the vendors that publish no reset rule on the pages we checked, we omit the claim rather than assume one.
Why do you not rank detectors by accuracy?
Because we have not tested detection accuracy, and publishing a ranking we have not measured would be inventing authority. This is a pricing record: it tracks what these tools charge, with dated evidence for every number. Accuracy is a separate research question that needs controlled evaluation.
How often is this page checked?
Tracked pricing pages are re-checked on a weekly cycle with a full re-verification at least monthly. The "Last verified" date at the top of this page changes only when the data was genuinely re-checked, and each table carries its own capture date.