Compound Interest

What your money does while you work, and what waiting costs you.

[ your numbers ]

Starting pot

Added monthly

Annual growth

Years

yrs

Total you'd pay in over the period £130,000

Where you end up

£271,000

That's 2.1× what you paid in.

Monthly compounding at your growth rate, contributions added each month.

How it splits

£141,000

is pure growth, on top of the £130,000 you put in.

The longer it runs, the more the growth share takes over. Time does the heavy lifting.

[ how it builds ]

From year 9, the pot earns more each year than you pay into it.

What you paid in Growth on top

Each bar is the pot at that point, split into your money and the growth riding on it. Early on it's mostly you; later it's mostly the compounding.

[ explore either lever ]

Growth rate

Same money in, different rate.

Rate: 7.0%

£271,000

The cost of waiting

Start later, finish on the same date.

Start in: 5 years

£171,000

Model: growth compounds monthly at a constant rate, with contributions added at the end of each month. Real returns move around and this ignores fees, tax and inflation — treat it as the back-of-envelope case. Not financial advice.

[ the honest bit ]

Compounding doesn't only work on savings

Every business owner nods along to compound interest and then runs their firm on straight lines. But your business compounds too, in both directions. A process that wastes an hour a day quietly compounds into a member of staff you didn't need to hire. A margin point you never claw back compounds into the van, the yard, the pension you funded for someone else.

The same maths runs the other way. Automate the quoting, the chasing, the paperwork, and the hours you get back don't just save money once — they free you to win work, which funds more improvement, which frees more hours. That's a compounding loop, and it's the reason a few percent of efficiency found this year is worth far more than the same percent found in five years.

The chart above already told you the punchline: the expensive thing isn't the rate, it's the waiting.

Want this projection sent over?

I'll email you these numbers so you have them on file, and if you tell me a bit about your business I'll show you where the same compounding logic applies to it. No pitch unless you ask for one.

Name

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