Quick presets
OptionalInputs
RequiredMonthly Savings Schedule
| Month | Quit survival prob | Cigs avoided | Direct spend avoided | Replacement cost | Healthcare offset | Net saved | Cumulative saved | Investment balance |
|---|
Example Data (inputs)
| Parameter | Example Value | Notes |
|---|---|---|
| Price per pack | 12 | Local store price. |
| Cigarettes per pack | 20 | Typical pack size. |
| Cigarettes per day | 15 | Use packs/day instead if preferred. |
| Inflation per year | 4% | Assumed growth of cigarette prices. |
| Invest annual return | 6% | Balanced long-run assumption. |
| NRT cost per day | 2 | Temporary replacement costs. |
| Replacement duration | 2 months | After that, zero replacement cost. |
| Healthcare offset | 0 / month | Add if premiums eventually drop. |
| CO₂ per cigarette | 14 g | User-adjustable assumption. |
| Horizon | 60 months | Five-year projection. |
How to use this calculator
- Optionally choose a country preset then adjust values.
- Enter price, pack size, and cigarettes/day or packs/day.
- Pick a quit date to see savings already accumulated.
- Choose horizon months for the projection length.
- Adjust price inflation and investment return assumptions.
- Optional: add replacement cost and duration, healthcare offset.
- Optional: enable relapse modeling for expected-value results.
- Click Calculate to update KPIs, schedule, and exports.
This tool provides financial estimates only and is not medical advice.
Formulas used
Daily spend previously
daily_spend = price_per_pack × (cigarettes_per_day ÷ pack_size)
If packs/day is provided, cigarettes/day = packs/day × pack_size.
Monthly avoided spend with inflation
month_days ≈ 365.25 ÷ 12
infl_m = (1 + inflation_annual)^(1/12) − 1
avoided_m = daily_spend × month_days × (1 + infl_m)^(m−1)
m is the month index (1..N).
Net monthly savings
net_m = avoided_m − replacement_cost_m + healthcare_offset_m
Replacement cost applies for the first chosen months.
Investment compounding
r_m = (1 + invest_annual)^(1/12) − 1
balance_0 = 0
balance_m = (balance_{m−1} + max(net_m,0)) × (1 + r_m)
Contributions made monthly and grown to end of horizon.
Relapse probability modeling (expected value)
S_0 = 1
p = relapse_monthly_probability
S_m = S_{m−1} × (1 − p)
expected_net_m = S_m × (avoided_m − replacement_cost_m + healthcare_offset_m)
expected_cigs_m = S_m × cigarettes_per_day × month_days
time_saved_minutes = expected_total_cigs × minutes_per_cigarette
CO₂_avoided_kg = (expected_total_cigs × grams_CO₂_per_cigarette) ÷ 1000
When enabled, schedule and KPIs use expected values scaled by survival.