See your savings grow over 10, 15 and 25 years.

Enter what you have and what you can put aside each month. See the result after fees, tax and inflation — and which choice gets you furthest.

Estimates, not advice. Returns are never guaranteed and investments can fall. The example numbers are typical levels you can change. Nothing you type leaves this page.

Your plan

Pick a market to load typical numbers, then change anything.

Market Currency Starting amount Put in each month Expected return a year % Before fees. Savings accounts pay about 0–5%. Broad stock index funds have averaged around 6–8% over long periods, with big ups and downs. Yearly fee % Fund or account fee (TER). Index funds charge about 0.05–0.3%, many other funds 1–2%.

Tax on the growth Taken from the growth when you cash out.

Inflation a year % Used to show the result in today’s money. Goal Optional. We’ll work out what to put in each month to get there.

What you could have

After fees and tax. Grey is the money you put in, green is the growth.

Compare your choices

The same monthly amount, with one thing changed. Green is the best result for each period.

What makes the biggest difference

Worked out from your numbers.

Year by year

How the money you put in and the growth add up.

After tax Money you put in In today’s money

Keep going in Flowjar

Open these numbers in the Flowjar app’s compound interest calculator, then give the monthly amount its own savings jar so you can watch it fill up.

Free on Android. Coming soon on the App Store.

How it’s worked out

How is the growth worked out?

The yearly return, minus the yearly fee, is turned into a monthly rate and added every month. Each monthly amount goes in at the end of the month. Real returns go up and down from year to year; this shows a steady average.

How is tax handled?

To keep it simple, tax is taken once from the total growth when you cash out, at the rate you pick. In real life, interest and dividends may be taxed every year, there are yearly allowances, and tax-free accounts have limits: NISA in Japan, ISA in the UK and Korea, 401(k) and IRA in the United States. The same tax setting is used for every row in the comparison.

What is “today’s money”?

Prices usually rise every year. “Today’s money” divides the future amount by the inflation you enter, so you can see what it would buy now. Central banks in Europe, Japan, Korea and the US aim for about 2% a year.

Where do the example numbers come from?

They are rounded, typical levels: savings and deposit rates published by central banks and banks in 2025–26, and long-run average returns of broad stock index funds. Past returns don’t tell you future returns. Use numbers that fit what you actually plan to do.

Is what I type saved anywhere?

No. Everything is worked out in your browser. The numbers are kept in the part of the link after “#”, which browsers don’t send to our server, so you can bookmark or share a comparison.