Question 1

What is the difference between Fast scan and Deep scan?

Accepted Answer

Fast scan runs the core pattern checks and answers instantly — it is built for quick looks and working through many texts. Deep scan runs every check ScanForAI has, including our trained deep-analysis model over each section of the document, and takes a few seconds. Deep is substantially more accurate and much less likely to flag human writing by mistake.

Question 2

When should I use Deep scan?

Accepted Answer

Whenever the answer matters: before you rely on a result, raise it with someone, or let it touch a grade or a decision. Deep scan is free with a free account, so there is no cost reason to settle for the quick check on anything important.

Question 3

Is Fast scan accurate?

Accepted Answer

Fast scan is honest about being a first pass. It is tuned to avoid flagging human writing, which means it deliberately trades away some ability to catch AI text — a clean fast result is not a guarantee. Treat a fast score as 'worth a closer look or not', and use Deep scan for the real read.

Question 4

Do Fast and Deep scan cost anything?

Accepted Answer

Both are free. Fast scan needs no account at all. Deep scan is free with a free account — the account is the abuse guard, not a paywall.

	Fast scan	Deep scan
What runs	The core pattern checks — sentence rhythm, phrasing, predictability, typography — combined by a trained scoring profile.	Everything. The full pattern set plus our trained deep-analysis model, run across every section of the document, with the strictest calibration we have.
Speed	Instant. Milliseconds of computing — which is also why it is unlimited.	A few seconds. Roughly a thousand times more computing per document.
Accuracy	A deliberate trade: tuned first to avoid flagging human writing, at the cost of catching less AI. A clean fast result is not a guarantee.	Substantially more accurate in both directions — catches far more AI and is far less likely to flag a person by mistake.
Built for	Quick looks. First passes. Checking a batch of entries fast. Deciding what deserves a closer read.	Grades, submissions, disputes, editorial calls, anything you might act on or show to someone else.
How to read it	As a screening pass: "clear", "worth a deep check", or "leaning AI". The middle answer is the honest one surprisingly often.	As our best read of the document — score, per-sentence marking, and the evidence behind every signal that fired.
Price	Free, no account, unlimited.	Free with a free account — the account is the abuse guard, not a paywall.

Fast scan vs Deep scan. Pick deliberately.

Deep for anything important. Fast for speed and volume.

Fast is tuned to be safely wrong, not confidently wrong.