AI Prompt for Compound Growth Projections and Fee Drag Analysis

What you need

You need your current invested assets and your ongoing monthly investment additions. Exclude emergency cash deposits from the invested asset line if that cash sits in low-interest transaction accounts, because cash reserves do not compound at equity market rates.

In the context section of the snapshot template below, make sure you state your monthly contribution amount clearly. The projection formulas rely on continuous monthly cash additions to demonstrate how regular savings interact with investment compounding over five, ten, twenty, and thirty years. State your numbers in a single currency so the compounding calculations maintain mathematical consistency throughout the entire timeline. If your investment contributions happen quarterly rather than monthly, divide the quarterly figure by three to establish an average monthly rate.

Use the snapshot block below as your data container. Fill in your current balances, copy the text block, and paste it into your AI session alongside the prompt below.

Here is my financial snapshot. Use only these numbers.

Currency: [e.g. EUR]
Date: [today's date]
Age: [optional]

ASSETS
[name] — [category: cash / stocks / ETFs / crypto / property / metals / other] — [value]
[name] — [category] — [value]
...

LIABILITIES
[name] — [type: mortgage / car loan / credit card / student loan / other] — [outstanding balance] — [interest rate if known]
...

CONTEXT (optional but improves the answer)
Monthly income after tax: [amount]
Monthly spending: [amount]
Amount I add to savings or investments each month: [amount]
Value of the same assets 12 months ago: [amount]

The prompt

Copy this exact text and paste it into ChatGPT, Claude or Gemini directly beneath your snapshot block.

You are a financial educator. Using my snapshot above:

1. Take my current invested assets and my monthly contribution and project the
   balance at 5, 10, 20 and 30 years, at 3%, 6% and 9% annual growth. Present it
   as a table.
2. Separate how much of each final figure came from my contributions and how much
   came from growth.
3. Show what happens to the 30-year figure if I start five years later.
4. Show what a 1% annual fee takes out of the 30-year figure.
5. Explain in plain language why the later years move so much more than the early
   ones.

State every assumption. Note that these are illustrations and not forecasts.

What good output looks like

The output should begin with a clean markdown grid showing four timeline milestones: five years, ten years, twenty years, and thirty years. For each milestone, it displays projected portfolio balances across three annual growth rates: three percent, six percent, and nine percent. The model must assume monthly compounding intervals and state that baseline assumption clearly.

Underneath the table, the model must break down each thirty-year outcome into two distinct components: cumulative principal contributed out of pocket versus cumulative compound interest generated. In thirty-year scenarios at six or nine percent, compound returns dwarf the total cash invested, demonstrating the tipping point where investment earnings outpace annual savings.

The cost of delay section calculates the thirty-year balance if you delay regular contributions by five years, holding total duration to twenty-five years. It highlights the permanent capital penalty imposed by missing that initial five-year compounding runway.

Next, the model quantifies fee drag by running the thirty-year projection at five percent instead of six percent, isolating the impact of a one percent annual management fee. It shows how a seemingly minor one percent fee consumes twenty to twenty-five percent of your potential end balance.

The output concludes by explaining exponential curvature in simple physical terms: during later decades, compound gains generate their own returns, creating larger monetary jumps in single years than during the entire first decade.

What this can't tell you

This prompt models steady, uninterrupted annual returns, whereas equity markets experience volatile cycles with substantial annual drawdowns. A portfolio averaging seven percent annualized returns over thirty years will experience severe down years that mathematical compounding tables do not portray.

The model cannot foresee tax drag from annual dividend distributions or capital gains taxes on rebalanced funds. It does not account for sovereign inflation that erodes the real purchasing power of your future nominal balances. Language models frequently make compounding calculation errors when compounding monthly over decades, so verify table numbers with an offline financial formula. The output serves as an educational illustration rather than a personalized investment forecast.

Doing this without the retyping

Testing compounding scenarios with external chatbots means retyping your portfolio totals and contribution amounts whenever your monthly surplus or base capital changes. In Sumio, this compounding analysis is one of sixty-two prompts built directly into the app. It runs with one tap against the holdings you already track, keeping growth models aligned with your current balances. Your financial records stay stored on your device, with no account required and no ads.