Navaraj Thapa
Software engineer and systems architect Kathmandu, Nepal
I spent ten years studying and working in the UK, then fifteen more in IT in Nepal — across retail, ISP, healthcare, fintech and media, most recently as CTO of a media company. HealthGuide is one of a few things I build and run independently.
I am not a doctor, a dietitian, or a clinician of any kind, and nothing on this site is medical advice. What I can offer is the other half of the problem: most health calculators on the web are black boxes. They give you a number and never tell you where it came from, what it assumes, or when it stops being meaningful.
So every calculator here that I have reviewed shows three things explicitly — the method it actually uses, the limitations of that method, and citations to the published research its thresholds come from. Where a score is my own composite rather than a validated instrument, it says so in plain language rather than borrowing authority it hasn't earned.
How these tools are built
- Published formulas first. Where a peer-reviewed instrument exists — the PSS-10, waist-to-height ratio thresholds — it is implemented as published, without private adjustments.
- Composites are labelled. Some scores combine several inputs in a way no paper defines. Those are described as heuristics, and the weighting is spelled out so you can judge it.
- Sources are named and linked. Author, year, journal. If a claim has no source I can point at, it does not go on the page.
- Nothing leaves your browser. Every calculation runs locally. Your measurements are not sent anywhere unless you choose to save a profile.
- Corrections welcome. If something here is wrong — a threshold, a citation, a formula — I would rather hear it and fix it.
Our mission
Health Guide exists to make evidence-based health tools accessible to everyone — for free, with no account required, and with complete respect for your privacy. Every number our calculators produce comes from the same population-based equations used in clinical research and public health guidelines.
How it works
Science-backed formulas
Our 11 calculators use established equations — Mifflin-St Jeor for BMR/TDEE, the U.S. Navy method for body fat, Devine and Robinson formulas for ideal weight, and Karvonen for heart rate zones. These are the same reference formulas used in dietitian offices and sports medicine clinics.
Private by design
Any health data you enter — age, weight, height, activity level — stays in your browser's localStorage. It is never sent to our servers, never stored in a database, and never shared with third parties. You can delete it at any time by clearing your browser data.
Priority-driven Health Planner
Our Health Planner is not a generic checklist. It runs all 11 calculators silently against your profile, assigns each result an urgency score from 0–100, and surfaces the top action in each health pillar — Move, Eat, and Live. You see only the three things that matter most for you today.
Calculators and the formulas behind them
| Calculator | Formula / Method |
|---|---|
| BMI | WHO standard: weight (kg) ÷ height² (m²) |
| BMR | Mifflin-St Jeor (1990) |
| TDEE | BMR × Harris-Benedict activity multiplier |
| Body Fat % | U.S. Navy circumference method |
| Ideal Weight | Devine (1974), Robinson (1983), Miller (1983) |
| Calories Burned | MET values (Ainsworth et al., Compendium of Physical Activities) |
| Macro Split | AMDR ranges (Institute of Medicine dietary reference intakes) |
| Heart Rate Zones | Karvonen heart rate reserve method |
| Waist-to-Height Ratio | WHO boundary values (0.5 threshold) |
| Water Intake | EFSA and U.S. National Academies AI values |
| Pregnancy Due Date | Naegele's rule (LMP + 280 days) |
Important notice
All results from Health Guide are estimates based on population averages. They are not medical advice and do not account for individual health conditions, medications, or clinical history. Always consult a qualified healthcare provider before making changes to your diet, exercise, or health routine. See our full Medical Disclaimer.
Elsewhere
HealthGuide is an independent project. Its calculators are informational tools, not diagnostic ones, and they are not a substitute for advice from a qualified healthcare professional. If a result concerns you, speak to your doctor.