How long it lasts —
and when you clear.
Clearhead estimates how long a substance is likely to affect you and when it clears — across six substance families, with blood, saliva and urine windows. Private, offline, built on published pharmacology. Never dosing advice.
No account · No trackers · Works fully offline
Six substance families, honestly modelled.
Most tools give one generic THC number. Clearhead covers six families — each with its own pharmacology, detection windows, and combination-danger warnings.
An honest tool, not a shortcut.
Built on published science, calibrated on real impairment studies — not a meaningless concentration number. It flags dangerous combinations and busts detox myths, with sources.
What happens on your phone, stays on your phone.
No account, no analytics, no ads, no trackers. Everything you enter stays on your device and works fully offline. The only data that ever leaves is the anonymous purchase record for the optional Premium subscription.
Read our Privacy PolicyFree to download. Yours to keep private.
Try every feature live right after you install — 5 full estimates a month free, and all safety guidance is always free. All six substance families, science-backed. Premium unlocks unlimited estimates, extra charts and live tracking.
Not a medical device · Not permission to drive · The safest choice is always none.