This engine is the working model for one Chicago household. It is not advice. Change every slider. If you use our defaults you are walking our path, not a generic “high earner” path.
What it opens with
- First portfolio draw at 55 in 2030 — that is the first withdrawal year, not “quit all work.”
- After-tax pile of $2.75 million.
- Core lifestyle of $144,000 in 2026 dollars ($12,000 a month).
- Collar of 75%–125% of that core ($108k–$180k).
- Self-paid health gap of $36,000 from 55 until Medicare, unless you move the gap start later.
- Partner 1 Social Security at 70. Partner 2 may claim at 62.
- Kid slice and mortgage slice already inside core; they fall off after 2036 and 2040.
Host the Streamlit app at calculator.tamisin.com (Community Cloud or your own box). Point that hostname at the same app.py and config.json that ship with this site. Until the host is live, run locally:
streamlit run app.py
How to read it
The illustration path is one seeded sequence. It is a story, not a forecast. The Monte Carlo panel is the decision layer: how often the same rules run out of money across hundreds of markets.
If the failure rate is high, the answer is not a cleverer bucket. The answer is a later first draw, a larger after-tax pile, or a smaller month.