Wealth Growth Visualizer

The Wealth Growth Visualizer lets you compare several saving and investing plans on a single chart. Instead of running one compound-interest projection at a time, you overlay up to three combinations of monthly contribution and annual return rate and watch how the gap between them widens year after year. It is built to answer the questions that matter most: How much does an extra percent of return really cost me over 30 years? Is saving an extra $100 a month worth it? What does playing it safe leave on the table?

Why Compare Scenarios Side by Side?

Compound growth is famously hard to picture. A single curve tells you where one plan ends up, but it hides the opportunity cost of the choices you did not make. When two or three trajectories are drawn on the same timeline, the shaded gap between them makes the trade-off impossible to ignore. Early on the curves sit almost on top of each other; over the years they fan out dramatically — a direct, visual demonstration of why small differences in rate and contribution compound into life-changing sums.

How Wealth Growth Is Calculated

Each scenario is projected with monthly compounding and monthly contributions. The annual return rate is divided by twelve to get a monthly rate, the balance earns that rate each month, and the monthly contribution is added at the end of every month.

Here \(P\) is the starting amount, \(C\) is the monthly contribution, \(i\) is the monthly rate, and \(N\) is the total number of months (12 × years). The first term grows your starting lump sum; the second is the future value of a stream of equal monthly deposits.

The Two Levers: Rate vs Contribution

Wealth growth is driven by two inputs you can actually compare with this tool:

How to Use This Visualizer

1. Set the basics: Pick your currency, enter your starting amount (use 0 if you are starting from scratch), and choose how many years to project.
2. Define your scenarios: Enter a monthly contribution and an expected annual return rate for each scenario. The first is required; add a second and third to compare conservative, moderate, and aggressive plans.
3. Click Visualize Growth: Every scenario is overlaid on one animated timeline chart.
4. Read the gap: See how far the scenarios diverge, each plan's final balance and compound growth, the year-by-year comparison table, and a step-by-step formula breakdown.

Choosing Realistic Return Rates

There is no guaranteed return, so the smart approach is to compare a range. A diversified stock portfolio has historically returned roughly 6–8% per year after inflation over long periods, bonds and high-yield savings tend to be lower, and individual results vary widely. Run a cautious scenario alongside an optimistic one rather than betting on a single number. To approximate inflation-adjusted growth, subtract your expected inflation from the rate; for an after-tax view in a taxable account, reduce the rate by your tax drag.

Frequently Asked Questions

What does the Wealth Growth Visualizer do?

It projects how an investment or savings balance grows over time under several different assumptions at once. You enter a starting amount, a time horizon, and up to three combinations of monthly contribution and annual return rate. The tool overlays each scenario on a single timeline chart so you can see, side by side, how much the outcomes diverge over the years.

How is the wealth growth calculated?

Each scenario compounds monthly. The annual return rate is divided by 12 to get a monthly rate. Every month the balance earns one month of interest and then the monthly contribution is added. This repeats for 12 months times the number of years. The final balance equals your total contributions plus the compound growth earned along the way.

Why does the gap between scenarios widen over time?

Because of compounding, returns are earned not only on your contributions but also on previously earned returns. A higher rate or larger contribution earns slightly more each year, and that extra amount itself compounds. The difference is small early on but grows exponentially, so the gap between a conservative and an aggressive scenario widens dramatically over long periods.

What return rate should I use?

A common long-run assumption for a diversified stock market portfolio is around 6 to 8 percent per year after inflation, while high-yield savings or bonds are often lower. There is no guaranteed rate, so it is wise to compare a conservative, a moderate, and an optimistic scenario. This tool is designed for exactly that kind of side-by-side comparison.

Does the tool account for inflation or taxes?

Not directly. The projection shows nominal balances before inflation and taxes. To approximate real, inflation-adjusted growth, enter a return rate that already has expected inflation subtracted (a real rate). For after-tax results in a taxable account, use a return rate reduced by your effective tax drag.

Can I compare just one scenario?

Yes. Only the first scenario is required, so you can project a single saving plan on its own. To unlock the side-by-side comparison and the widening gap band, fill in a second or third scenario with different contribution or return assumptions.

Additional Resources

• Compound Interest - Wikipedia
• Future Value - Wikipedia