World Salary Calculator
A dollar is not worth the same everywhere, even after you convert it. Purchasing power parity (PPP) is the tool economists use to measure what money can actually buy from one country to the next.
Imagine two friends who each earn the equivalent of $40,000 a year at market exchange rates, one in Toronto and one in Mexico City. On paper they are equal. In practice, the friend in Mexico City pays far less for rent, meals out and haircuts, so the same income stretches much further. PPP puts a number on that gap.
What PPP actually means
PPP says that, over the long run, the same goods should cost the same in every country once prices are converted into one currency. Economists call this the law of one price.
The logic is simple. If a laptop cost far less in one country than another, traders would buy it where it is cheap and sell it where it is expensive. That trade would push prices, and eventually exchange rates, back toward balance.
Because one product can be misleading, PPP is measured with a basket of goods and services: food, clothing, housing, transport, healthcare and so on. Compare what that whole basket costs in each country and you get a PPP exchange rate, the rate at which two currencies would buy exactly the same things.
A worked example
In this made-up example, the PPP rate is 40 rupees per Canadian dollar, but the market gives 60, so a Canadian visiting India gets about 50% more purchasing power than the exchange rate alone suggests.
Suppose the same basket of everyday goods costs:
| Country | Basket price |
|---|---|
| Canada | C$100 |
| India | ₹4,000 |
The PPP exchange rate is the ratio of the two prices:
PPP rate = price in India ÷ price in Canada = 4,000 ÷ 100 = 40 rupees per C$
Now suppose the market exchange rate is 60 rupees per Canadian dollar. Converting C$100 at the market rate gives ₹6,000, enough to buy the Indian basket 1.5 times. In PPP terms, the rupee is cheap relative to what it buys at home, or equivalently the Canadian dollar is strong.
The figures here are illustrative, chosen to keep the arithmetic easy.
The Big Mac Index: PPP on a bun
The most famous everyday version of PPP uses a single burger. Since 1986, The Economist has published the Big Mac Index, which compares the price of a Big Mac across dozens of countries.
The Big Mac works well as a mini-basket because it is made to the same recipe almost everywhere and bundles local costs: beef, bread, wages, rent and electricity. If a Big Mac costs noticeably less in a country (after converting at market rates) than in the United States, the index treats that country's currency as undervalued; if it costs more, the currency looks overvalued.
It began as a light-hearted teaching tool, and economists treat it that way: a quick, memorable check rather than a precise measurement. The Economist's Big Mac Index publishes the current figures.
Where PPP shows up in the real world
PPP matters most when someone needs to compare living standards fairly across borders.
- Comparing the size of economies. The World Bank and the IMF publish GDP both at market exchange rates and at PPP. Countries with lower prices, such as China and India, look considerably larger when measured at PPP.
- Measuring poverty. The World Bank's international poverty line is set in PPP dollars, so it represents the same real buying power in every country.
- Comparing wages and salaries. Employers and researchers use PPP to judge whether a salary in one country is genuinely higher or lower than in another, after living costs.
- Judging currencies. When a market exchange rate sits far from its PPP rate, analysts read it as a sign the currency may be over- or undervalued.
The PPP rates behind these figures come from the International Comparison Program, a World Bank–coordinated effort that collects prices for a common basket in nearly every country.
Two flavours: absolute and relative PPP
Absolute PPP is the strict version: the exchange rate should equal the ratio of price levels, exactly as in the worked example above.
Relative PPP is looser and holds up better in the data. It says exchange rates should change in line with the difference in inflation between two countries. If prices rise 6% a year in one country and 2% in another, the first country's currency should weaken by roughly 4% a year against the second.
% change in exchange rate ≈ inflationA − inflationB
This is why countries with persistently high inflation tend to see their currencies fall steadily over time.
Why the real world doesn't follow PPP
Market exchange rates can stay far from PPP for years. A few forces keep them apart:
- Many things can't be traded. You can't ship a haircut, a restaurant meal or an apartment across a border, so their prices never get evened out by trade.
- Trade costs. Tariffs, taxes, shipping and regulation make it expensive to move even tradable goods.
- Different baskets. People in different countries buy different things, and quality varies, so no single basket fits everyone equally.
- Money flows, not just goods. In the short run, exchange rates are driven far more by interest rates, investment, speculation and central bank decisions than by the price of groceries.
- Richer countries are pricier. Higher wages make local services more expensive, so wealthier countries tend to have higher price levels (often called the Balassa–Samuelson effect).
The upshot: PPP is a good long-run anchor and a strong tool for comparing living standards, but a poor guide to where a currency will trade next month.
The bottom line
Purchasing power parity answers a simple question: how much can this money actually buy here? Market exchange rates tell you what a currency trades for; PPP tells you what it is worth in daily life.
Next time you compare salaries across countries, plan a long stay abroad, or read that one economy is "bigger" than another, check whether the figures are at market rates or at PPP. The answer can change the story completely.
To see how much of a salary you keep after tax in each country, read How much of your salary do you keep? or try any of our calculators from the menu at the top of the page.