exchange rate

Imagine you fly from New York to Tokyo with 100 US dollars in your pocket. The moment you land, those dollars are useless for buying a bowl of ramen — the shop wants yen. So you go to a counter and swap your dollars for yen, and the cashier tells you that 1 dollar gets you about 150 yen. That number — how much of one country's money you get for one unit of another's — is the exchange rate. It is simply the price of one currency expressed in terms of another.

An exchange rate is always a ratio between two currencies, so it can be written two ways that mean the same thing. If 1 US dollar equals 150 Japanese yen, then 1 yen equals about 0.0067 dollars. People usually quote it in the direction that gives a tidy number. A change in the rate changes how far your money goes abroad: if the dollar moves from 150 to 160 yen, each dollar now buys more yen, so Japan has become cheaper for an American tourist. If it moves from 150 to 140, the dollar buys fewer yen and Japan has become dearer. The rate moves constantly during trading hours, second by second, like the price of any heavily traded good.

Exchange rates matter far beyond holidays. Every imported phone, every barrel of oil, every overseas factory wage and every foreign loan is ultimately priced through an exchange rate, so the rate quietly shapes the price of goods on your shelves, the profits of exporters, and the size of a country's foreign debt. A common confusion is direction: a 'stronger' or 'higher' currency means it buys more foreign money, which is good for importers and travellers but can hurt exporters, whose goods now look expensive abroad. There is no single 'right' level — a rate that helps one group hurts another.