$↔₩ · Exchange Rate
An exchange rate is 'the price of one unit of foreign currency' — when it rises, the foreign currency got pricier, meaning your own money got weaker against it.
The euro 'rose' from $1.05 to $1.25 — did your dollar's power grow?
What are we trying to understand?
'The rate went up' betrays intuition. Up sounds good — but what rose is the price of the other currency. Your trip to Europe gets pricier while exporters celebrate.
A rate is just the price tag on 'one euro'. When apples get pricier, apple sellers smile; when euros get pricier, those who earn euros (exporters) smile and those who spend them (travelers, importers) wince.
Get the direction right and currency news becomes readable. Add the exchange spread and you can compute why an airport kiosk quietly takes 3–7% on a round trip.
Change one assumption at a time
The result follows the inputs and assumptions. Check the units and model before treating it as an actual outcome.
Predict first — the rate rose from $1.05 to $1.25 per euro. Your dollar's buying power in Europe?
Move the rate
As the rate rises, watch which way each number moves.
a €100 item
$105
import price
your $1,000
€952
converted to euros
Read the calculation another way
If the exchange rate rises, my currency strengthened.
The opposite. The $/€ rate is 'the dollar price of one euro' — a rising rate means the euro got pricier and the dollar weakened against it. 'Rate up' and 'dollar strong' are antonyms here.
Currency exchange happens at the published mid-market rate.
The mid-market rate is only a reference. Buy and sell prices differ (the spread) — typically 1–3% per direction at kiosks. Exchange and immediately exchange back, and several percent is simply gone.
Why the calculation works, and when
The directions confirmed in the experiment, written as formulas.
The definition
E is 'the dollar price of one euro'. A €100 item costs $105 at E=1.05 and $125 at E=1.25.
The opposite pull
The same $1,000 buys €952 at E=1.05 but only €800 at E=1.25 — a rising rate shrinks your dollar's buying power abroad.
Round-trip loss
A spread s charged on the way out and the way back costs about 2s. At s=3% per direction, a round trip loses about 6%.
Try the idea in another setting
Overseas shopping and travel
A 10% rate rise makes European hotels and imports 10% pricier in dollars — plus your card network's 1–3% foreign transaction fee at settlement.
Exporters' earnings
The same €100M of export revenue converts to $105M at 1.05 and $125M at 1.25 — why exporters' stocks often rise when their home currency weakens.
Commodities and inflation
Oil, wheat, and gas trade in dollars. When a country's currency weakens, import prices climb and reach supermarket shelves months later — exchange rates lead inflation.
Where you exchange matters
Airport kiosks often charge 5%+ per direction; a good app charges near 0.5%. The same vacation cash can cost ten times more in fees depending on the counter.
Now explain it in your own words
Follow the mathematics behind the calculation
Related lab
Ratios
An exchange rate is the ratio between two currencies — a feel for ratio direction IS currency sense.
Go to the Ratios lab →Previous lab
Percent
Spreads and fee discounts are all percent arithmetic — pack your base-value sense first.
← Percent labRecommended next
Unit Price
You've compared currencies by ratio; now compare products — unit price reveals the real bargain.
Go to the Unit Price lab →