Twenty-three beautifully made health calculators and a considered AI GP chat — private by design. Every calculation runs on your phone. No accounts. No data harvesting. Just clarity.
Health data is the most personal data there is. So Prescriba keeps it where it belongs — on your device, in your hands. Nothing is uploaded, nothing is sold. Just careful tools, grounded in real evidence, that help you understand your own body.
From BMI and calories to ovulation, HbA1c and prostate scores — each one instant, private, and cited. Tap any tool to use it free in your browser.
Body Mass Index with category & healthy weight range.
Open →Mifflin–St Jeor BMR, TDEE and a daily calorie target.
Open →US Navy circumference method with lean/fat mass.
Open →A realistic timeline and daily target for a safe pace.
Open →Predict your next period and current cycle phase.
Open →Your ovulation day and fertile window.
Open →Due date & current week (Naegele's rule).
Open →A weighted symptom checklist, for education.
Open →Rate daily symptoms and track their severity.
Open →See what smoking really costs you, over years.
Open →UK NHS units in your drinks and weekly total.
Open →Half-life decay of caffeine in your system.
Open →The 20-20-20 rule with a gentle timer.
Open →Daily check-ins, streaks and a 7-day heatmap.
Open →Fitzpatrick skin type + UV index → SPF advice.
Open →Ask about a result, a symptom, or what a number means — and get a warm, plain-English answer grounded in evidence. It never lectures, never alarms, and never replaces your doctor. It simply helps you walk into that appointment prepared.
Twenty-three tools, an AI GP, and a private health journal — all in one calm app. No account, no data harvesting.
Download on the App StoreOn the App Store · iOS 17+ · Free