ABOUT
Built by one person, with citations.
Yearfold is an independent retirement calculator. No VC funding, no affiliate-funnel agenda, no hidden upsell. Below: who built it, why, and what we deliberately won’t do.
I’m a senior technology executive and Principal Cloud Solutions Architect with 30+ years designing, implementing, and optimizing mission-critical cloud and AI systems for commercial enterprises and federal government agencies. My recent work has centered on the secure enterprise deployment of generative AI tools — the same kind of careful, documented engineering Yearfold applies to retirement modeling.
Important credentials caveat. I’m a software engineer, not a Certified Financial Planner, CFA, or tax attorney. I’m building Yearfold in public: the methodology is open, every data source is cited on the methodology page, and I’m in the process of contracting a credentialed CFP® reviewer to sign off on finance content before it ships. Until that reviewer is in place, finance pages render an “Editorial review pending” line rather than borrow credentials Yearfold doesn’t yet have. Nothing on this site is personalized investment, tax, or legal advice.
Why I built this
I started building Yearfold because every consumer retirement calculator I tried gave me an answer that I knew was wrong by construction. They treated my household as one earner. They ignored dependents. They returned a single “you’ll have $X at 65” number with no honest range — as if the future were one fixed line instead of a distribution. And the ones that did run real Monte Carlo were either locked behind a $999/year subscription (RightCapital, eMoney) or required handing over my bank credentials and signing into a 0.89% AUM advisory relationship (Empower). The middle was empty: serious probabilistic math, family-aware, 2026 tax and Social Security rules baked in, free, no account, no data linking. So I started building the calculator I wanted to use myself.
The retirement-calculator market today is still split between toy single-input tools (Bankrate, NerdWallet — fine for a rough sanity check) and enterprise software priced out of normal reach. Yearfold sits in the middle: the math is professional-grade, the price is free, and the family-aware modeling — couples, dependents, joint Social Security claim optimisation, 2026 IRMAA brackets — is the part that makes the answer actually match your household.
How Yearfold is built differently
Most consumer calculators pick a single “expected” return (e.g. 7% per year) and roll it forward in a straight line. That hides the only thing that actually matters in retirement planning, which is the range of plausible outcomes. Yearfold instead runs a Monte Carlo simulation: ten thousand parallel futures, each one a different plausible sequence of market returns and inflation, sampled with replacement from real monthly data from 1928 through 2025 (the “historical bootstrap” method). The output isn’t one number — it’s a distribution. You see the share of futures where your plan works (the success probability), the spread between the 10th, 50th, and 90th percentile ending balances (the fan chart), and the specific year-by-year picture of where the failing paths went wrong.
On top of that simulation, Yearfold layers the 2026 federal rules that actually determine your real after-tax retirement income: post-OBBBA federal tax brackets, the standard deduction (including the over-65 add-on), Social Security taxation thresholds (frozen at the 1983/1993 statutory amounts), the Medicare Part B base premium plus IRMAA tiers, and SECURE 2.0 RMD ages. Couples are modeled as two earners with two claim ages. Dependents add cost during their dependent years and drop out afterwards. Every assumption is documented on the methodology page and every load-bearing number traces to a primary source (SSA, IRS, CMS, FRED, Shiller).
What we won’t do
- We don't link to your bank or brokerage — your data stays in your browser.
- We don't recommend specific funds, ETFs, or advisors.
- We don't sell to financial advisors who pay for leads.
Our methodology
Every assumption Yearfold makes — from the 1928–2025 historical bootstrap to the 2026 IRMAA brackets — is documented and cited on the methodology page. If you find a number that’s wrong or a 2026 rule we missed, tell us — we update on a known cadence (SSA in October, IRS in November, Medicare in January).
Editorial review
Yearfold takes Google’s YMYL (“Your Money or Your Life”) standards seriously. Every page that cites a tax bracket, Social Security rule, or Medicare premium gets reviewed against the primary source on the cadence above, with the reviewer name and last-reviewed date stamped on the page.
Status: v1 content is reviewed by the founder against primary sources. We’re contracting a credentialed CFP® reviewer before launch to sign off on every methodology change. Until then, finance pages render “Editorial review pending” rather than borrow credentials we don’t have.
If you’re a fee-only CFP, CFA, or tax attorney interested in the reviewer role, write to hello@yearfold.com.
Contact
Questions or feedback? Email hello@yearfold.com.