Articles and studies

Studies with real data and dated analysis. Each one explains how it was calculated and links to a calculator so you can try your own numbers.

S&P 500 over 1, 5, 10, 20 and 30 years: best and worst returns

How much the S&P 500 can gain or lose depending on how long you hold it, across every possible period since 1928.

Every time the S&P 500 fell more than 20% from its high, how long it lasted and how long it took to recover.

If you have a sum to invest, is it better to put it in at once or spread it over several months? We tested every month since 1988.

Divide 72 by the return and you know how many years your money takes to double. Here is why it is so useful.

From cost to price: five ways to work it out and the mistakes that cost the most.

What cost €1,000 in 2015 cost €1,267.92 in 2025. What it means for your savings and what you can do.

The order you pay your debts in and what you put towards them each month change how long it takes and how much interest you pay.

Dividing the salary you want by the hours in a year gives rates that are too low. Here is the full formula.

Certainty or possible savings: what changes between fixed, variable and hybrid, with an example of how much the payment moves.

Comparing the payment with rent is incomplete. Here is how to work out the real cost of owning.

The 4% rule gives a quick figure: about 25 times your annual spending. We explain where it comes from and how long the money would last.

A simple way to split your income between needs, wants and saving, with an example and its limits.

Overpaying is an investment with a guaranteed return; investing may earn more, but with no guarantee. Here is how to compare them.