How the numbers are made
Forward: your amount buys the asset at the start month's price (gold and silver: world price in US dollars times the monthly average exchange rate). The same units are valued at the end month's price. That is the nominal value.
Real value: the nominal value is divided by how much your own country's consumer price index rose between the two months. We never deflate by US inflation for a non-US user.
Backward: today's amount is first deflated by your country's CPI to the start month, then divided by the asset price of that month. The plain-price figure skips the deflation.
Return per year uses the exact compound formula, multiple^(1/years) − 1, with years = months/12. It is shown only for periods of one year or more.
Prices are monthly averages. No fees, taxes or spreads are included. Currencies that were redenominated are shown in today's units. Quality grades A–D flag known problems in the official data.
Home prices are an index (BIS, OECD): your money grows with the index; no home is bought. Minimum wages and Big Macs are yardsticks, not investments: the amount divided by that month’s monthly minimum wage or Big Mac price. Turkey’s minimum wage is net; other countries’ are gross.