How Are Exchange Rates Calculated and Do They Change Every Second?
The exchange rate is the ratio between the price of one country's currency and that of another. It is a comparison between the two: the price of one country's currency in terms of another's. For instance, with USD/CNY at 7.25, that means you need 7.25 Chinese Yuan to purchase 1 American dollar. However, this price is not set by a single global authority; rather it is most often determined by the forces of supply and demand in international trading (Fx) markets—the largest financial market in the world.
The Mathematics of Exchange Rates: It's All About Supply and Demand
Contrary to what one might imagine, there is no definite formula just as E=mc² giving a real-time figure for exchange rates. The rate is marked by the last transaction price agreed upon between buyers and sellers in the market that day.
The Core Mechanism: When demand for a currency (let's say the Euro) exceeds its supply, its exchange rate (price) goes up; and when the sellers on hand outnumber buyers, the price falls. This process operates round-the-clock during market hours.
Practical Calculation: For a private citizen, contrasting the amount to be received is easy multiplication: those with 100 USD might find it doddle that 100 × 7.25 = 725 CNY. As to the opposite situation (how many USD one CNY there are ), the formula looks like 1 / 7.25 ≈ 0.138 USD.
Do Exchange Rates Really Change Every Second?
For the biggest freely-traded currencies like USD, EUR and JPY, the answer is yes. They do indeed change all the time during market hours – without any let-up.
The Forex market is open 24 hours a day, five days a week. With trillions of dollars traded daily and prices updating with every transaction, the foreign exchange market is volatile indeed, and it is not uncommon to see rates change many times per second due to algorithms competing against each other.
A matter of seconds after order submission--its status changed from 'waiting' to 'in processing'", recalls a professional FX trader with no small amount of wonder to his voice. The "Static Illusion" The quoted rate you see on bank apps and currency converter websites seems stable because it's based on snapshots of that day's trading. This number is simply the most recent update, not a constant value.
Why It Isn't Constant
Market moves by the second undercurrent, but daily life changes the equation.
Bank and App Rates: Disclosure in your pocket (like banking apps or airport exchange counters) is not updated in real-time. It may be refreshed every several minutes even once per day. Plus they add a "spread," fee, or commission on top of this market rate--mushy and gelatinous enough to blur differences between milliseconds.
Fixed and Controlled Currencies: Some currencies are pegged to another (like the Hong Kong Dollar to the USD) or tightly managed by their country's central bank. These rates change very slowly, and go up or down only when new policies shift them around from one day to next.
Key Factors That Influence Exchange Rate Changes
Even though you cannot see the prices moving, these basic forces are constantly re-engineering supply and demand.
Interest Rates: Countries with higher interest rates attract foreign investment capital increasing the demand for their money.
Economic Data: Reports on inflation, employment, and GDP growth can provoke immediate, sharp rate changes.
Geopolitical Events: Elections, trade wars, general instability lead to uncertain futures with volatile swings.
In short, exchange rates are dynamic prices set by the global market. Though they change with every second in inter-bank markets, the rates we use for travel or shopping are snapshots from these movements which are both delayed and marked up.
