Compound Interest Calculator ☆ Save

Why compounding is the only free lunch in finance

Compound growth means your returns start earning returns. Over short periods it is unremarkable; over long ones it does something that feels almost unfair — and the variable that matters most is not the rate, it is time.

Change the years in the calculator above and watch what happens. A decade you did not use costs more than any rate difference you will ever negotiate, which is why "start now with a small amount" beats "start later with a serious one" almost every time.

Use it to disprove a scam in thirty seconds

This calculator has a second use that is arguably more valuable in Zimbabwe than the first. Take any promised return and compound it.

A scheme offering "20% a month" turns US$1,000 into roughly US$8,900 in a year — and about US$79,000 in two.

Now ask the obvious question: if anyone could reliably do that, why are they recruiting strangers from a WhatsApp group with a US$50 minimum? Returns that would make someone the wealthiest person in the country within a few years are not being shared with people they have never met.

Run the promise through the calculator and believe the arithmetic rather than the person. Watching a pitch become absurd on screen is more persuasive than any warning. Our guide on spotting an investment scam in Zimbabwe covers the five structural tells that go with it — guaranteed returns, urgency, recruitment rewards, vague mechanisms, and withdrawals that suddenly become difficult.

What rate is realistic in Zimbabwe?

Anchor the projection to something real, or it tells you nothing:

• Savings accounts publish roughly 1%–3.5% a year — see our savings comparison. Safe storage with a modest yield, not growth;
• Equities can do more over long periods, with real risk of loss. VFEX is USD-denominated and by H1 2026 had overtaken the ZSE by market capitalisation — see investing on the ZSE and VFEX, including the thin-liquidity caveat;
• Anything guaranteeing far more, with no risk, is not an investment.

If you are projecting decades ahead, be conservative. A projection built on an optimistic rate is not a plan — it is a wish with a chart.

The three things that quietly reduce your real result

1. Inflation. The calculator projects nominal money. What matters is what that sum will buy — which is the strongest argument for saving in US dollars rather than the local unit. See ZiG vs USD explained;
2. Transaction costs. IMTT at 2% applies per electronic movement, so contributing four times a month costs four times the tax of contributing once. At Zimbabwean savings rates, a few unnecessary transfers can undo a year's interest;
3. Interruptions. The projection assumes you never stop. In practice people stop when an emergency arrives — which is why an emergency fund protects a long-term plan more effectively than a higher rate does.

The highest-return "investment" available to most households

Worth stating plainly, because it outranks anything this calculator will show you: clearing expensive debt is a guaranteed, tax-free return.

Zimbabwean consumer credit publishes rates reaching 20% per month, with a 228% APR ceiling elsewhere. No investment reliably beats not paying that. If you are carrying payroll loan debt, the debt payoff planner is the tool to use before this one.

Frequently asked questions

What rate should I enter?

For savings, use what your bank actually publishes (roughly 1%–3.5%). For long-horizon investing, be deliberately conservative — the projection is only as honest as its inputs.

Does this account for inflation?

No — it projects nominal amounts. Treat the result as "how many dollars", not "what it will buy", and save in the more stable currency to protect the difference.

Monthly contributions or one lump sum?

Both work; regular contributions suit most people because they match how income arrives. Just make them fewer and larger where possible, because each electronic transfer can attract the 2% transfer tax.

Someone promised me 20% a month. Should I?

Put it in the calculator and look at the two-year figure. Then read how to spot an investment scam. Guaranteed returns at that level do not exist.

Where do I actually put the money?

Start with a protected savings account — DPC cover is US$3,000 per depositor at a bank — and only move to investments once the emergency fund exists and expensive debt is cleared.

Projections are illustrative and assume a constant rate and uninterrupted contributions; real returns vary and are not guaranteed. Savings rates cited are as published by Zimbabwean banks and change without notice. General information, not investment advice.