ETF Savings Plan Calculator

How the calculation works

The plan is worked out month by month. The expected return is a yearly rate, so each month grows by the twelfth root of it. A 7% year is 12 months of about 0.565%, not 12 months of 7% / 12, which would add up to more than 7%.

Contributions are invested at the start of each month, quarter or year and grow from that day on. A yearly increase raises the contribution once per plan year, so a 3% increase turns 250 a month into 257.50 a month in the second year.

The TER is taken from the fund's assets a little every month, the way a real fund charges it, so a full year costs exactly the TER as a share of the value. The cost shown under the result is the difference between the plan with and without that fee. It grows with time because the money lost to fees also misses out on all later growth.

Inflation and today's money

Inflation does not change how the plan grows. It only translates the result into what it would buy today. With 2% inflation, 100,000 in 25 years buys about as much as 61,000 does now. In the Target tab you can enter the target in today's money and the tool inflates it to the end date for you.

Tax at sale

With tax at sale turned on, the tool taxes your gains as if you sold everything at the end. Gains are the final value minus everything you paid in. A partial exemption takes part of the gains out of tax first. Germany, for example, leaves 30% of the gains on equity funds untaxed. A tax-free allowance then removes a fixed amount of gains. The rest is taxed at your rate.

This is a simplification. It ignores taxes charged while you hold the fund, like Germany's yearly Vorabpauschale or tax on distributions, and it treats the allowance as a single amount at sale. Check the rules in your country before you rely on the after-tax figure.

Withdrawals

The Withdrawal tab takes the monthly amount out first and lets the rest grow for the month. With withdrawals raised by inflation, the amount goes up once a year so it keeps its buying power. The tool stops counting at 100 years. It also shows the monthly amount that leaves the starting capital untouched, which is what the money earns each month after costs. Tax is not applied in this tab.

What the numbers can't tell you

Real markets don't return the same rate every year. A plan with an average of 7% can still be well below its paid-in amount after a bad year, and the order of good and bad years matters a lot once you start withdrawing. Treat the result as one possible path, and try a lower return to see a more careful case.