WONKAI TOOLS · FREE · NO SIGN-UP
A little each month.
What could it add up to?
Choose an amount and a timeline. See your contributions and compare different return assumptions.
Just two things to choose.
Try an amount that feels comfortable.
Choose a year to see contributions and hypothetical growth at that point.
−99% to 100% · Up to two decimal places.
Returns are illustrative assumptions. Actual results will vary, and you could lose money.
Understand the numbers as you go.
Open a question for a short, plain-language explanation.
What is compounding?＋
Reinvested gains can earn gains of their own. This calculator assumes equal contributions at the end of every month and continued reinvestment. Actual returns can change from year to year.
Why include a 0% option?＋
At 0%, you see only the money you put in. Comparing it with other assumptions helps separate your own contributions from hypothetical investment growth.
Should I think about losses too?＋
Investments can fall in value. Try “What if it falls?” to see a decline as an actual amount of money. It is a way to think about what you could comfortably handle.
Your saved plans
Clearing browser data or closing private browsing can remove plans. Keep a shared link or image with amounts included if you want a separate copy.
For your next question.
Your original WONKAI calculators are here too. Currently in Korean.
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Calculation assumptions & privacy＋
Equal contributions are made at each month-end, with all returns reinvested. The annual return is converted to an equivalent monthly compound rate. Use the 0%, 3%, 5% and 7% presets or enter an illustrative annual return from −99% to 100%, with up to two decimal places. Goal mode reverses the same formula to find a monthly contribution, rounded up to the currency’s smallest displayed unit. Loss mode applies one percentage decline. KRW and JPY are displayed in whole units; other currencies use 0.01 units. Final values are rounded, and gains are the final value minus contributions. Losses are rounded first, then subtracted from the original amount so displayed totals balance. Charts, saved plans and shares use the same calculation.
Taxes, trading costs, exchange rates and inflation are excluded. This is not a stock recommendation, a live quote or a forecast. Changing currency does not convert amounts.
Inputs and saved plans stay on your device. Including amounts in a share puts them in the link and image. Plan data is stored after # in the link and excluded from analytics. Visits and button usage are counted anonymously.