How is compound interest calculated here?

Your initial amount grows at the expected annual return, and each monthly contribution is added and then compounds for the remaining months. Returns are applied monthly at one twelfth of the annual rate, which is a standard simplification.

What return should I assume for a Swiss portfolio?

There is no correct number. A common approach is to run a pessimistic case around 3%, a base case around 5% and an optimistic case around 7%, then treat the spread as the plausible range rather than trusting a single figure.

Why does the inflation-adjusted value matter?

It translates the final amount into today's purchasing power. A portfolio that grows 4% per year while inflation runs at 1.5% only gains about 2.5% in real terms, which is what actually determines what you can buy later.

Are fees and taxes included?

No. Enter a return that is already net of fund costs and platform fees if you want a realistic figure. Swiss wealth tax and tax on dividends are not modelled in this tool.

Investing

Compound Interest Calculator

See how an initial investment plus regular monthly contributions could grow over time in Swiss francs. Adjust the return and inflation assumptions to understand the range of possible outcomes — all results are estimates.

Your investment

Initial investment

Monthly contribution

Investment period

Assumptions

Expected annual return

A broadly diversified equity portfolio has historically returned roughly 5–7% per year before fees, with large swings.

Annual inflation

Used to express the final amount in today's purchasing power.

Yearly increase of contribution

Invest at the start of each month

Estimated value after 20 years

CHF 233'500

Approximately CHF 183'940 in today's purchasing power at 1.2% inflation.

Total contributions

CHF 130'000

Initial amount plus all monthly payments

Estimated investment gains

CHF 103'500

44.3% of the final value

Inflation-adjusted value

CHF 183'940

In today's francs

Contributions vs. growth

The dark area is money you paid in. The green area is the estimated growth on top of it.

Your contributions Estimated investment gains

After 10 years

CHF 94'435

CHF 83'816 in today's francs

After 15 years

CHF 155'338

CHF 129'889 in today's francs

After 20 years

CHF 233'500

CHF 183'940 in today's francs

What these numbers mean

Compound interest means your returns start earning returns themselves. In this projection you pay in CHF 130'000 in total, and the estimated growth on top of that is CHF 103'500 — that is 1.80× your contributions after 20 years, an effective 2.97% per year on the money you invested.

Inflation quietly reduces what your money can buy. At 1.2% inflation, CHF 233'500 in 20 years would feel like about CHF 183'940 today. This is why holding everything in a Swiss savings account with a low interest rate can lose purchasing power over long periods.

Real markets do not deliver a smooth annual return. A realistic way to use this tool is to run a pessimistic case (for example 3%), a base case (5%) and an optimistic case (7%) and treat the spread as the plausible range.

Returns are assumed to be constant every month — real markets fluctuate, sometimes heavily.
Monthly contributions are compounded monthly (interest is added every month, and then earns its own interest) using the annual return divided by twelve.
No product costs, fund fees, custody fees, trading fees or spreads are deducted.
No Swiss taxes are modelled: Swiss capital gains on private assets are generally tax-free, but dividends and interest count as taxable income (income that is added to your tax bill) and wealth tax may apply.
Inflation-adjusted values use a constant inflation rate to express the final amount in today's purchasing power.
Amounts are in Swiss francs (CHF); currency risk of foreign investments is not modelled.

This calculator provides approximate, educational estimates only. It is not investment advice, a forecast, or a guarantee of future returns.

It does not consider your personal situation, fees or tax position. Your inputs stay in your browser and are never sent to a server.

How is compound interest calculated here?: Your initial amount grows at the expected annual return, and each monthly contribution is added and then compounds for the remaining months. Returns are applied monthly at one twelfth of the annual rate, which is a standard simplification.
What return should I assume for a Swiss portfolio?: There is no correct number. A common approach is to run a pessimistic case around 3%, a base case around 5% and an optimistic case around 7%, then treat the spread as the plausible range rather than trusting a single figure.
Why does the inflation-adjusted value matter?: It translates the final amount into today's purchasing power. A portfolio that grows 4% per year while inflation runs at 1.5% only gains about 2.5% in real terms, which is what actually determines what you can buy later.
Are fees and taxes included?: No. Enter a return that is already net of fund costs and platform fees if you want a realistic figure. Swiss wealth tax and tax on dividends are not modelled in this tool.

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Contributions vs. growth

What these numbers mean

Assumptions usedFor anyone curious about exactly how we calculate — feel free to skip this part.

Frequently asked questionsShort answers to the questions that come up most often with this calculator.

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