The Cost of Waiting & the Rule of 72 — Why Every Year Matters

Your Quick Math for Growing Money

When it comes to growing your money, there’s one thing even more powerful than the perfect investment: time and the simplest way to understand the magic of time is through something called The Rule of 72.

Here’s the tea: Take the number 72 and divide it by your annual interest rate (or return on investment). The answer is roughly how many years it will take your money to double.

For example: If your investment earns 8% per year: 72 ÷ 8 = 9 years

So, every 9 years, your money doubles — without you lifting a finger.

The High Price of “I’ll Start Later”

The Rule of 72 makes it painfully clear how costly it is to wait.

Let’s say you invest £10,000 at 8%:

• Start now: In 9 years → £20,000. In 18 years → £40,000. In 27 years → £80,000.

• Wait 9 years to start: In 9 years → £20,000. In 18 years → £40,000.

That delay just cost you £40,000 — without spending a penny. That’s the power of compounding… or the cost of missing it.

So what's the Takeaway

The earlier you start, the more time your money has to double… and double again. You don’t need a fortune to begin — you just need to begin. Because in the end, it’s not timing the market that matters most, it’s time in the market.