FREE · US RETIREMENT PLANNER · 2026 DATA
10,000 futures.One honest plan.
The retirement calculator that factors in your spouse, your kids, and reality — not just a cheerful average. Runs 10,000-path Monte Carlo with 2026 Social Security, Medicare, and inflation data built in.
Data sources
LIVE EXAMPLE · COUPLE AGE 45 · $380K SAVED
10,000 simulations
Y-axis scaled to median path’s peak. Some simulations exceed this range.
median $2.3M · 10th pct $890K · depletion age 91
Real Monte Carlo — not a single “average” answer.
Not just averages.
10,000 simulated futures show the probability of success — and the shape of the tail.
Your spouse and kids, modeled.
Dual earners, dependent care, and legacy impact — not a single-person average.
Specific shortfall fixes.
"Contribute $340 more/month OR retire 14 months later" — not vague warnings.
WHY THIS WORKS
Built on the same math the brokerages use, made honest about uncertainty.
Vanguard, Fidelity, and Schwab all run Monte Carlo simulations to model retirement uncertainty. Yearfold uses the same methodology — 10,000-path historical bootstrap from 1928–2025 market data — but makes the assumptions visible and the output specific. Every number on this site traces to a primary source. Every plan is shareable via URL. The math is open; only the implementation is ours.
BUILT ON THE BEST PUBLIC DATA
Same methodology as the major brokerages — radically more transparent.
Yearfold runs the same Monte Carlo methodology you’ll find in Vanguard, Fidelity, Schwab, ProjectionLab, and Boldin — but with every assumption, every data source, and every result published. Most calculators don’t show their work. We do.
METHODOLOGY
10,000-path Monte Carlo, 1928–2025 historical bootstrap
MARKET DATA
Robert Shiller / Yale online data
INFLATION
U.S. Bureau of Labor Statistics CPI-U
SOCIAL SECURITY
Social Security Administration 2026
HEALTHCARE & TAXES
CMS 2026 Medicare + IRS contribution limits