Wealth growth across three decades

Simulating Your Wealth Growth

Wealth growth is not linear — it's exponential. The most important insight from running wealth simulations is that the last 10 years of a 30-year journey produce more wealth than the first 20 combined, thanks to compounding acceleration in later periods.

Why the Starting Point Matters More Than People Realise

Many people focus entirely on how much they save each month. That matters, of course. But your current net worth — whatever it is right now — is already working for you. Even a modest starting figure, given enough time and a reasonable return, can grow into something quite significant. It can help to think of your existing wealth as seeds already in the ground. The annual savings you add are simply more seeds. Time is the sunlight. One approach is to run the simulation at different starting points to see how sensitive your outcome is to that initial number — many people find the results quite eye-opening.

Common Oversights When Modelling Wealth

A few things are worth considering before taking any simulation at face value. Inflation quietly erodes purchasing power over long periods, so a large nominal figure in 30 years may feel smaller in real terms. Tax is another factor that varies enormously depending on individual circumstances. And return assumptions matter hugely — small differences in the expected annual return, compounded over decades, produce dramatically different outcomes. Trying a range of return scenarios, rather than anchoring to one optimistic figure, tends to give a more balanced picture of what the future could look like.

Quick example

With current net worth of 20,000 and annual savings of 12,000 (plus expected annual return of 7 and years to simulate of 30), the result is 1,382,300.95. Change any figure and watch the output shift — it's often more useful to see the pattern than to memorise the formula.

Which inputs matter most

You enter Current Net Worth, Annual Savings, Expected Annual Return, and Years to Simulate. The rate and the time horizon usually dominate — compounding means a small change in either reshapes the final figure more than a similar shift in contribution size. Test this by doubling one input at a time.

What's happening under the hood

This simulator applies the future value formula combining compound growth on the initial net worth with regular periodic contributions. It assumes a constant annual return rate and annual compounding with no fees or withdrawals. Results are illustrative projections showing potential wealth accumulation over the chosen timeframe. The formula is listed in full below. If the number looks off, you can retrace the calculation by hand — that's the point of showing the working.

The annual review habit

Plug new numbers in every year. Income changes, expenses shift, markets move. A plan that isn't revisited quietly drifts out of date. This tool is cheap to re-run — so re-run it.

What this doesn't capture

Real plans get re-run against new information every year or two. The result here is a reasonable direction, not a destination. Treat it as a starting point for thinking, not a commitment to a specific future.