Enter model inputs
Use the multi-column calculator area below for flexible health-state input.
Example data table
This example illustrates a typical four-state pathway with discounting and comparator analysis.
| State | Duration (years) | Utility | Raw QALY contribution |
|---|---|---|---|
| Stable disease | 1.20 | 0.82 | 0.9840 |
| Treatment response | 0.80 | 0.91 | 0.7280 |
| Progression | 0.60 | 0.56 | 0.3360 |
| Supportive care | 0.40 | 0.38 | 0.1520 |
Formula used
Base QALY: QALY = Σ(utility × duration)
Discounted QALY: Discounted QALY = Σ[(utility × duration) ÷ (1 + r)t]
ICER: ICER = (Intervention Cost − Comparator Cost) ÷ (Intervention QALYs − Comparator QALYs)
This page multiplies each health-state utility by its duration to calculate raw QALY contribution. Discounting adjusts later gains using the annual rate you provide.
When half-cycle correction is enabled, the page discounts each state at its midpoint. That usually provides a better approximation for period-based cohort models.
How to use this calculator
- Enter the discount rate, cohort size, comparator QALYs, costs, and willingness-to-pay threshold.
- Add one row for each health state, then enter duration in years and the matching utility weight.
- Enable half-cycle correction when your model assumes transitions happen throughout each interval.
- Submit the form to see discounted QALYs, incremental outcomes, ICER, cohort totals, and the Plotly graph.
- Use the CSV and PDF buttons to export the generated results tables for reporting or review.
FAQs
1) What does QALY mean?
QALY stands for quality-adjusted life year. One year lived in perfect health equals 1.00 QALY. Lower health quality reduces the value proportionally, while states worse than death can be entered as negative utilities when your framework allows them.
2) How is this calculator different from a life expectancy tool?
This calculator combines duration and health-related utility, not survival alone. It values both longer life and better quality of life, making it useful for treatment comparison, health economic modeling, and cost-effectiveness reporting.
3) Why would I use discounting?
Discounting reduces the present value of future health gains. Many evaluations discount later benefits because decision makers often prefer earlier gains. Enter your annual rate to align results with your guideline or analytic protocol.
4) What is half-cycle correction?
Half-cycle correction assumes events occur throughout a period, not only at the end. It discounts each period at its midpoint, which usually improves approximation when states represent broad annual or multi-month intervals.
5) Can utility values be negative?
Yes. Some models allow values below zero for health states considered worse than death. This page accepts negative utilities, but you should use ranges that match your instrument, valuation method, and policy guidance.
6) What is incremental cost-effectiveness ratio?
ICER equals incremental cost divided by incremental QALYs. It shows the extra cost required to gain one additional quality-adjusted life year compared with a comparator. Interpret it alongside your willingness-to-pay threshold.
7) Should comparator QALYs be discounted too?
Usually yes, when your intervention QALYs are discounted. For a fair comparison, use consistent assumptions, time horizons, and discount conventions across both options before interpreting incremental outcomes or reimbursement decisions.
8) Can I use this for cohort totals?
Yes. Enter the cohort size to scale discounted QALYs from per-patient values to total program values. This is helpful for budget impact summaries, portfolio reviews, and service planning discussions.