What is compound interest?

Compound interest is when you earn return not only on the initial amount, but also on previously accumulated interest. The base grows each period, multiplying gains. For example, $10,000 at 15% annual return doubles in about 5 years and quadruples in 10 years. The longer the horizon and the more regular your contributions, the stronger the effect.

Why include inflation in calculations?

Inflation erodes money: at 7% per year, purchasing power halves in about 10 years. The nominal balance grows, but real value — what you can buy — may lag. The calculator shows both nominal growth and real value in today's money so you see the true outcome.

What does «real return» mean?

Real return is return minus inflation. If nominal rate is 15% and inflation 7%, real return is about 8%. Only it reflects how much you're actually getting richer. The calculator computes it automatically and shows «Real total» and «Income above inflation».

Do I need to register? Is my data saved?

No registration needed. All calculations run in your browser. Data is saved only locally (localStorage) — amounts, parameters, currency, theme, custom contributions. Nothing is sent to a server. To clear — clear site data in browser settings.

Is the calculator free?

Yes. The calculator is free, no subscription or ads. Use it as much as you like.

Can I plan for retirement?

Yes. In «Savings forecast» mode there's a block with date of birth and retirement age (55, 60, 65 or other). The calculator applies years to retirement automatically. Useful to estimate how much to save and what passive income it will provide.

What does «index contributions» mean?

In «Index» mode you set the amount in today's money. Each month the nominal contribution grows by inflation — so the real value of what you save stays constant. This is realistic for long-term goals: wages typically rise with inflation, and you can save «the same in purchasing power».

What is «safe to spend per month»?

The maximum monthly spending at which real capital value doesn't decrease. Part of capital income must stay on the account (inflation compensation), the rest is real income you can spend. Spending more — inflation starts «eating» capital.

Is it safe to invest for 20 years ahead?

Historically long-term investments in a diversified portfolio (stocks, bonds) have delivered positive real returns. Key is not to withdraw during drawdowns, reinvest income, and account for inflation. The calculator helps plan but doesn't give financial advice — discuss major decisions with a professional.

What currencies are supported?

Amounts can be displayed in any currency from central bank rates: ruble, dollar, euro, hryvnia, Belarusian ruble and many others. Conversion is for display only; calculations use the selected currency.