A 4% high-yield savings account sounds safe. In nominal dollars, it is. At these assumptions, against a typical Family basket — housing in your zip, childcare, healthcare — it's losing roughly 3 points a year.
Safety in nominal dollars is not the same as safety against the life you want.
The arithmetic
A representative Family basket weighted 30% housing + 25% equity-linked aspiration + 20% childcare + 15% private K–12 tuition + 10% healthcare currently inflates at roughly 7.0% per year, 5-year trailing. Components, rounded:
- Housing (national, Case-Shiller
CSUSHPINSA, 5-yr trailing): roughly 6.5% - Equity-linked aspiration (S&P 500 Total Return, 5-yr trailing): roughly 13.1%
- Childcare (BLS
CUUR0000SEEB03, 5-yr trailing): roughly 4.8% - Private K–12 tuition (BLS
CUUR0000SEEB02, 5-yr trailing): roughly 3.9% - Healthcare (BLS
CUUR0000SAM, 5-yr trailing): roughly 2.4%
Aspire Rate, at this basket, is roughly 7.0%. That's the rate your money needs to grow at to keep pace with the cost of the life you're pricing.
A 4% high-yield savings account, against a 7% Aspire Rate, leaves you with an Aspire Gap of roughly −3 points. Every year. Compounded.
What a 3-point gap actually does over time
A $100,000 balance growing at 4% reaches roughly $148,000 in 10 years. That's the safe-feeling number.
The same $100,000 priced against a basket inflating at 7% needs to reach roughly $197,000 in 10 years to keep pace. The 4% account gets you about 75% of the way there. The other 25% — roughly $49,000 — is the gap that keeps growing.
This is not a story about being smart with markets. It's a story about which goalpost you're racing. The savings account beats CPI. CPI is a national basket. CPI is not your life.
Why this is hard to see
Three reasons.
First, the savings account number goes up. Up feels like winning. Most people don't run a parallel calculation against the cost of the life they want.
Second, the loss is invisible until the goal is in arm's reach. You only notice you're 3 points a year behind the year you actually try to buy the house, enroll the kid, or carry the parent.
Third, the framing in personal finance writing favors the safe-vehicle story. CPI gets used as the benchmark. CPI ignores most of the basket of things people are saving toward.
What the Simulator does with this
The Simulator lets you test how different long-term assumptions affect your Aspire Gap over time.
Instead of treating inflation as a single number, the tool models the relationship between:
- the future cost of the things you want,
- the assets you already own,
- your contribution rate,
- and the growth assumptions applied to each category.
Small changes to long-run return assumptions, timelines, savings rates, or future goals can materially change the projected gap under different scenarios.
The purpose of the Simulator is not to recommend a portfolio or tell you what to buy. It is designed to help you explore how sensitive your future purchasing power may be to different assumptions over time.
At these assumptions, users often discover that cash-based growth rates may not keep pace with the future cost of aspirational assets over long horizons.
What to do with this
Use the Simulator to test how changes in savings rate, timeline, future goals, and long-term growth assumptions affect your Aspire Gap under different scenarios.
The goal is not to predict markets or prescribe decisions. It is to help you understand how different assumptions can impact future purchasing power over time.
Methodology footnote. All CAGR figures here are 5-year trailing through the latest available data as of 2026-05-13. Housing: S&P Cotality Case-Shiller U.S. National Home Price Index (CSUSHPINSA), Feb 2021 → Feb 2026, via FRED. Equity-linked aspiration: S&P 500 Total Return Index (SPXTR), Apr 2021 → Apr 2026. Childcare: BLS CPI-U Day care and preschool (CUUR0000SEEB03), Apr 2021 → Apr 2026. Private K–12 tuition: BLS CPI-U Elementary and high school tuition and fees (CUUR0000SEEB02), Apr 2021 → Apr 2026. Healthcare: BLS CPI-U Medical care (CUUR0000SAM), Apr 2021 → Apr 2026. Cash/HYSA comparison is an illustrative 4.0% assumption; FDIC April 2026 national savings deposit rate is 0.38%; actual HYSA rates vary by institution. The "$197,000 to keep pace" projection assumes constant CAGR and zero contributions over a 10-year horizon — Aspire's Simulator handles richer scenarios with contribution paths and tax-aware modeling (v2). Specific basket weights cited for the Family preset live in /methodology §2. Outputs are educational measurements at your current assumptions, not investment advice. Consult a fiduciary advisor before making financial decisions.