What Is Compounding and Why It Matters for Investors

Short answer: Compounding is earning returns on your past returns, so your money grows faster and faster the longer it stays invested.

How Compounding Works

When you earn a return, that gain is added to your principal, and the next period's return is calculated on the larger amount. Over time, returns generate their own returns, and the growth accelerates. This snowball effect is why early and sustained investing is so powerful.

Why Time Is the Key Ingredient

The longer your money compounds, the bigger the effect. Most of the wealth from compounding is created in the later years, so starting a few years earlier can make a dramatic difference to the final amount, even with the same monthly investment.

A Simple Illustration

Imagine investing a fixed sum every month. In the early years growth seems slow, but as the base grows, the annual gains begin to dwarf your contributions. Someone who starts in their twenties can end up far ahead of someone who starts in their thirties, even if the later starter invests more each month.

Reinvestment Is Essential

Compounding only works if returns stay invested. Withdrawing dividends or profits, or frequently switching investments, interrupts the process. Choosing growth options in mutual funds and resisting the urge to spend gains keeps the snowball rolling.

The Enemy: Interruptions and Costs

High fees, taxes from frequent trading, and panic withdrawals all reduce the compounding base. Even small annual costs compound against you over decades, so keeping costs low is part of harnessing compounding.

The Takeaway

Start as early as you can, invest regularly, keep costs low, and let your money sit and grow. Patience is the investor's greatest ally, and compounding rewards it generously over the long term.

This explainer was written by The Dispatch desk to answer a question readers commonly ask. It is general information, not personalised financial advice.