AI Apps That Detect Nail Biting: Every Option Compared

Which apps detect nail biting in real time?

Four, as of 10 September 2026: Stop Biting, Hands Off, Nailed and SmartBehavior. All four process video on-device.

All details below were re-verified against each vendor’s public website, and their app store listings where those exist, on 10 September 2026. Pricing and features change — confirm before buying.

Why do AI detectors work when willpower and bitter polish don’t?

Most nail biting is automatic — episodes start and finish below conscious awareness, which is why willpower, bitter polish, and manual habit trackers so often fail: they all require the awareness the habit bypasses. Habit Reversal Training, the best-evidenced behavioural treatment, names awareness training as its first component.

Camera-based AI detection automates exactly that component. A model watches for hand-to-mouth movement and fires an alert at the moment of occurrence, supplying awareness from outside. Every app on this page implements that same insight; they differ in platform, scope, price, and what’s built around the detector.

Which app is best for nail biting at a computer?

Stop Biting — our app, so read this row knowing that. It runs — uniquely in this group as of 10 September 2026 — as a no-install PWA in a web browser, on Mac or Windows. Detection uses MediaPipe hand and face models in WebAssembly, fully on-device, with no camera data sent during detection. It tracks bite-free streaks and a timestamped incident history, and pairs the detector with over 100 science-backed guides on habit reversal.

Pricing is published: $2.99/month or $29/year (~$2.42/month), with a 3-day free trial and no credit card.

Honest limits: it detects nail biting only, and there’s no native phone app — on mobile it runs as a web app, not an installed detector.

Which app is best for multiple BFRBs on desktop?

Hands Off (handsoffapp.com) is a Mac and Windows desktop app whose site markets detection for five common body-focused repetitive behaviors — listing nail biting, skin picking, eyebrow or eyelash pulling, ear picking, and nose picking. All processing is local; the site states no video is recorded, no personal data is collected, and the app is GDPR compliant. It also includes a statistics tracker that shows progress over time, so it measures as well as interrupts. It’s €2.99/month with a 3-day trial; no annual plan is listed.

If you have several BFRBs and work at a desktop, this is the strongest option in the category. See our full Stop Biting vs Hands Off comparison.

Which app is best for Mac users who don’t want a subscription?

Nailed (nailedapp.io) is a macOS menu bar app. Its site advertises $4.99 as a one-time purchase, while the Mac App Store listing it links to currently shows the app as a free download with no in-app purchases — so check the store page for the price that applies to you. It uses the same MediaPipe-via-WebAssembly approach as Stop Biting, entirely on-device: the camera feed is processed in memory and discarded, with no servers and no analytics. When it detects biting, it flashes the screen red with an optional beep. Its store listing also describes offline nail-biting tracking.

No free trial is listed, it needs macOS 12 or later on an Apple M1 Mac or newer, and it’s Mac-only — but if you want the cheapest credible detector and dislike subscriptions, Nailed is it. See our full Stop Biting vs Nailed comparison.

Which app is best for phone-based detection?

SmartBehavior (smart-behavior.com) is the only entrant with native mobile apps: iOS, Android, plus Windows via the Microsoft Store. No dedicated macOS app is listed, though its App Store listing states the iPad app runs on a Mac with an Apple M1 chip or later. It detects nail biting, skin picking, hair pulling and other BFRBs, claims 85% detection accuracy, runs 100% offline on-device, requires no registration, and tracks daily, weekly, and monthly trends. Pricing isn’t published on its website — its US App Store listing showed $0.99, and storefront prices vary, so check yours.

If most of your biting happens away from a computer, this is the option built for that. See our full Stop Biting vs SmartBehavior comparison.

How do I choose between these nail biting apps?

Match the app to where your habit lives, not to feature counts.

Bite mainly at a computer, want tracking and a method around the alarm: Stop Biting — and the free trial needs no card, so testing it costs nothing.

Multiple BFRBs (skin picking, brow pulling, ear picking) at a desktop: Hands Off.

Apple Silicon Mac user who wants nothing recurring: Nailed — and check its App Store page, which listed it free when we last looked.

Bite mainly away from the computer, want it on your phone: SmartBehavior.

Whichever you pick, the mechanism is the same evidence-aligned idea: automate the awareness that habit reversal training requires and the habit itself suppresses.

Frequently asked questions

Every answer below rests on the same 10 September 2026 check of the four vendors’ own websites and app store listings.

Are there any free nail biting detection apps?

Nailed’s Mac App Store listing showed the app as a free download with no in-app purchases when we checked, though its own site advertises $4.99. Stop Biting has a 3-day free trial that needs no credit card.

Do these apps upload your camera feed?

No. All four process video on-device: Stop Biting and Nailed run MediaPipe models in WebAssembly, Hands Off states all processing is local, and SmartBehavior states it works 100% offline.

Which of them detect more than nail biting?

Hands Off lists five BFRBs — nail biting, skin picking, brow or lash pulling, ear picking and nose picking — and SmartBehavior covers nail biting, skin picking, hair pulling and other BFRBs. Stop Biting and Nailed detect nail biting.

Is there a nail biting detection app for iPhone or Android?

SmartBehavior has native iOS and Android apps. Stop Biting runs on a phone as a web app rather than an installed detector.

How we verified this page

Every competitor claim in the table above was re-verified on 10 September 2026 against handsoffapp.com, nailedapp.io, smart-behavior.com and the App Store listings those sites link to. Three of the corrections that pass produced went against us, and they are worth naming: Hands Off ships a statistics tracker and lists a fifth behaviour, ear picking, that we had left out; Nailed’s App Store listing now shows the app as a free download and describes nail-biting tracking, both of which this page previously denied it; and SmartBehavior’s iPad app runs on Apple Silicon Macs, which we had presented as a gap. We re-check quarterly rather than writing a comparison once and leaving it to rot, and we date it here so you can judge how current it is. Prices and features change — confirm on the vendor’s own site before buying.

A note on medical advice

This article is for general information only and is not medical advice. Nail biting and related body-focused repetitive behaviours (BFRBs) can have medical and psychological dimensions that deserve individual attention. For diagnosis or treatment — of BFRBs, infections, or any condition discussed here — consult a qualified professional: a GP or dermatologist for physical symptoms, or a therapist experienced with BFRBs for the habit itself. The TLC Foundation for Body-Focused Repetitive Behaviors (bfrb.org) maintains a directory of BFRB-informed clinicians.

Related reading

• Stop Biting vs Hands Off: which should you pick?
• Stop Biting vs Nailed: subscription vs a Mac menu bar app
• Stop Biting vs SmartBehavior: which fits where you bite
• Best tools to stop nail biting, ranked by evidence
• Habit Reversal Training: the clinical method