Tool · real data

What if I had invested…?

The time machine we've all wished for. Choose how much, when and in what, and see what it would be worth today, its yearly return and the worst moment along the way.

This tool needs JavaScript enabled in your browser.

Your numbers

Bought at that month's close.

Assumptions and how it's calculated

What it calculates. It buys the chosen amount at the close of the start month and values it at every month-end close up to the latest data point. With dividends reinvested it uses the total return series (every dividend goes back in); without them, just the price. Index figures are those of the indices themselves, with no product fee, except when the fund that tracks them is used for dividends.

Currency. By default, in the asset's currency. If you choose euros or dollars, each month's euro/dollar rate is applied, so you also see the currency effect, which sometimes helps and sometimes hurts.

Value in month t = C × (S_t ÷ S_0) × currency adjustment Total return = Value today ÷ C − 1 Yearly return = (Value today ÷ C)^(1/years) − 1 Worst fall = biggest drop from a previous high, using month-end closes C: amount invested · S: price (or index level) at month end

What it leaves out. Taxes, trading and custody fees, and falls within a month (with daily closes, the worst fall is usually a bit bigger). The large companies on the list are the ones that made it big: looking only at today's winners makes the past look easier than it was.

This is an exercise based on your assumptions, not a recommendation.

The past teaches a lot, but it never repeats itself exactly.

· Data: monthly closes; "with dividends" uses prices adjusted for dividends and splits (for indices, their total return index or their exchange-traded fund).

Invitation only, for now

We’re a small group and we like growing slowly, so accounts can’t be created right now: membership is by invitation. If you’d like to join, drop us a line and we’ll tell you more.

Already have an invitation? Activate it here →

Email us

Invitation only, for now

We’re a small group and we like growing slowly, so accounts can’t be created right now: membership is by invitation. If you’d like to join, drop us a line and we’ll tell you more.