Have you ever noticed that the same item costs differently in different countries? For example, coffee costing $5 in the USA might be $2 in Thailand. This is not just a difference in prices—it's a matter of purchasing power parity, or as it's often called, PPP.

Purchasing power parity is a tool that helps compare how strong a currency really is. Imagine: you want to understand which currency gives you more goods for the same amount of money. That's what PPP is for.

It all starts with the so-called "law of one price." It sounds simple: if a product is the same everywhere, then after converting at the exchange rate, its price should be the same. But in practice, taxes, transportation, and local demand interfere. Therefore, economists don't look at a single product but take a whole basket—food, clothing, housing, energy—and compare how much they cost in different countries.

What does this PPP give us? First, when talking about a country's GDP, without purchasing power parity, the picture becomes distorted. Take India: its GDP per capita appears extremely low at the regular exchange rate. But if you consider that living there is cheaper, it turns out that people live better than it first seems. The IMF and the World Bank use PPP-adjusted data precisely to more honestly represent the wealth of different countries.

Second, PPP helps compare living standards. The same $50,000 will allow you to live comfortably in one place, but in another, it might only cover survival.

Third, it's a tool for predicting exchange rates. Although they fluctuate due to politics and speculation, in the long run, they tend to return to levels indicated by PPP.

The most famous example is the Big Mac Index. An economist noticed: since burgers are roughly the same everywhere, why not compare their prices? If a Big Mac costs $5 in the USA and $3 in India, that immediately shows the difference in currency purchasing power. Later, similar indices for iPads and KFC appeared—everything to make PPP more understandable.

But there are also problems. The same item might be of better quality in one country—and then prices are not entirely comparable. There are also goods that are not traded between countries at all—real estate, hairdressing services, electricity. Their prices depend on local conditions and vary greatly. Plus, inflation can spoil everything—what's true today might be outdated in a few months.

How is all this related to cryptocurrencies? Not directly, but very indirectly. Bitcoin and other crypto assets are global assets, not tied to any country. But in countries with weak currencies (according to PPP), people often use crypto and stablecoins to protect their money from inflation. If your currency loses purchasing power, crypto becomes a safety cushion. This is especially relevant in countries experiencing hyperinflation. Stablecoins help people preserve their purchasing power when the local currency drops.

In the end, purchasing power parity is not just a theory for economists. It's a way to understand the real state of the economy, people's actual incomes, and the real cost of living. Maybe you're planning to move, maybe you're an investor, or maybe you're just curious why things are cheaper abroad—either way, PPP will help you understand this.