An open, evidence-based tool for exploring how everyday habits shape your projected healthy years. Transparent weights, private by design, honest about its limits.
Healthspan — the years you live in good health, free from serious chronic disease or disability — matters more to most people than raw lifespan. Yet most online calculators either hide their methodology or overstate their precision.
Helixspan takes a different approach. Every weight is published on the homepage. The assumptions are stated plainly. The limitations are front and centre. The score is a guide for reflection, not a clinical risk assessment.
Every factor weight is published on the homepage. The methodology page explains exactly how the score is calculated, and citations link to open-access studies.
Your inputs never leave your browser. No account, no tracking, no server receiving your health data. Everything runs locally in JavaScript.
Weights are drawn from large population studies — GBD 2019, Li et al. 2018, UK Biobank meta-analyses, and WHO HALE data. Sources are cited for every factor.
The model is a deliberate simplification. It doesn't capture genetics, medications, access to care, or dozens of other factors that influence real health outcomes.
Most people know that smoking is bad and exercise is good. The difficulty is turning that abstract knowledge into a felt sense of consequence. Helixspan tries to close that loop — not by moralising, but by showing a plausible range of outcomes as you move the sliders.
The immediate, real-time feedback from adjusting an input is deliberately designed to make the relationship between habit and outcome visceral rather than statistical.
It is a tool for reflection, not a diagnostic instrument. Use it alongside conversations with your doctor, not instead of them.
The Helixspan model has three components, each documented in full in the methodology section of the homepage.
We start from HALE at birth for high-income populations — roughly 70 years for men and 73 for women — and add or subtract years based on lifestyle inputs. HALE measures years lived in good health, not total lifespan.
Each of the seven factors contributes a year delta drawn from the plausible ranges published in the source studies. The total possible range spans roughly −14 to +3 years relative to the population baseline.
The raw healthspan estimate is rescaled to a 0–100 score centred at 72 — the population average for high-income countries. Bands: At risk (below 50) · Fair (50–64) · Strong (65–79) · Excellent (80+).