Currency Exchange Rates Explained: How They Work and Why They Change

0
17

Last reviewed: September 2026

The amount of foreign currency you receive affects the cost of overseas travel, purchases, and payments. When you convert Singapore dollars, currency exchange rates determine the value exchanged, while applicable fees can affect the final amount received.

A quotation becomes more useful when you understand the currency pair, the direction of conversion, and the difference between reference and customer rates. Market conditions also influence how those rates change over time. Understanding these details helps you interpret quotations and calculate conversions more accurately, while DBS provides a currency converter for checking rates before you review and confirm your transaction.

Quick Summary

  • Currency exchange rates express one currency’s value relative to another.
  • A stronger Singapore dollar buys more of a given foreign currency.
  • Supply, demand, and economic expectations influence market movements.
  • At a hypothetical rate of US$0.75 per S$1, S$100 converts to US$75 before fees.

What Are Currency Exchange Rates?

Currency exchange rates are prices showing how many units of one currency correspond to a unit of another.

  • Currency codes identify the money involved: SGD represents Singapore dollars, while USD represents US dollars.
  • An exchange rate is a ratio, whereas a transaction fee is a charge.

According to the Bank for International Settlements, “Trading in OTC FX markets reached $9.6 trillion per day in April 2025.” This US-dollar figure covers spot transactions and derivatives across the global over-the-counter foreign exchange market.

Why Exchange Rates Matter for Everyday Spending

A fixed overseas expense, such as a university tuition payment, can require a different amount in Singapore dollars when payment falls due. For regular overseas funds transfers, this makes the conversion date relevant to household budgeting.

Foreign currency savings also change in SGD value as rates move, so budgeting estimates should use a dated quotation and allow for possible changes.

How Currency Exchange Rates Work

Reading a Currency Pair

In a currency pair, the first currency is the base currency and the second is the quote currency. SGD/USD shows US dollars per Singapore dollar. Dividing one by that rate gives the inverse quotation.

Understanding Buying, Selling, and Reference Rates

When reading currency exchange rates, identify whether the figure is a transaction price or a benchmark. For a provider quoting SGD per US dollar, buying and selling describe the provider’s side of the transaction.

Rate typeWhat it representsHow to use it
Buying rateProvider’s price for buying your USD.Selling USD for SGD.
Selling rateProvider’s price for selling you USD.Buying USD with SGD.
Mid-market rateMidpoint between market buying and selling quotations.Comparing a customer quote with a market benchmark.
Reference ratePublished benchmark calculated using a stated method.Context, according to the publisher’s intended use.

The difference between buying and selling prices is the spread, separate from any transaction fee. The European Central Bank states that its reference rates “are published for information purposes only,” so use your provider’s applicable transaction rate when calculating a conversion.

Calculating the Converted Amount

  • Input: Amount available for conversion and the applicable rate.
  • Process: Multiply the base-currency amount by the quoted rate.
  • Output: Amount received after any deducted charges.

Fees deducted upfront reduce the amount converted, while fees paid separately increase your total outlay. DBS provides instructions for exchanging foreign currencies through digibank.

Why Currencies Rise and Fall

Currency demand changes as businesses pay overseas suppliers and investors move money between countries. Several influences help explain these shifts:

  • Interest-rate expectations: Higher expected returns can attract investment into a currency, although perceived risk also matters.
  • Economic conditions: Inflation and growth prospects influence purchasing power, competitiveness, and investor confidence.
  • News and sentiment: Unexpected economic data or political developments can prompt investors to reassess their currency holdings.

These influences interact, so the same announcement can produce different reactions depending on market expectations.

Policy arrangements also shape movements. Floating currencies respond largely to market forces, while central banks may intervene to keep managed currencies within a target range.

Exchange Rates in Practice: Three Everyday Examples

These hypothetical calculations use US dollars per Singapore dollar and assume fees are zero.

  • Travel budget: S$1,500 × US$0.80 = US$1,200 available for overseas expenses.
  • Overseas bill: US$600 ÷ 0.80 = S$750 needed to pay the full amount.
  • Different quotation: S$1,500 × US$0.79 = US$1,185, giving you US$15 less than the first example.

The first calculation starts with a spending limit, the second with a payment obligation, and the third measures the effect of a rate difference.

For funds you intend to spend later, DBS My Account supports holding multiple currencies, including SGD and 12 foreign currencies. The conversion date can therefore differ from the date you spend the funds.

Common Misconceptions About Exchange Rates

Myth: A higher rate always offers better value

Reality: Compare quotations for the same currency pair and conversion direction.

Myth: Displayed rates remain available

Reality: Indicative quotations may refresh before you confirm.

Myth: Fee-free means cheapest

Reality: Compare the total SGD payable for the same foreign-currency amount.

Myth: Buying and selling rates are interchangeable

Reality: Converting money and immediately converting it back can reduce your balance through the spread.

Myth: Recent gains reveal the best conversion time

Reality: Future prices depend on new information and changing expectations.

Frequently Asked Questions

Are foreign exchange rates and currency exchange rates the same thing?

Yes. Both terms describe the same concept, and “FX” is a common abbreviation for foreign exchange.

How often do exchange rates change?

Market rates fluctuate during trading. The European Central Bank usually updates reference rates around 16:00 Central European Time each working day, except TARGET closing days.

Why does my bank’s rate differ from a reference rate?

A bank’s quote reflects its pricing and transaction type. Differences in publication timing can also explain a gap against a reference rate.

Do I multiply or divide to convert currencies?

Multiply for a rate expressed as destination currency per unit of starting currency, and divide for the reverse quotation. First divide any rate quoted per 100 units by 100.

Can I know the best time to exchange money?

No. The most favourable rate becomes clear only afterwards. Base your decision on your budget and payment deadline.

Where can I check DBS exchange rates?

Check the DBS Currency Converter online. In digibank, choose “View Exchange Rates” while setting up a currency exchange.

Check Currency Exchange Rates Before Your Next Payment

Use currency exchange rates to assess what your budget will buy or what an overseas payment will cost. Before proceeding, confirm the conversion direction, applicable charges, and final amount.

Check your quotation with the DBS Currency Converter, then review the transaction details when you are ready to exchange.

Reference and Source Links

  1. https://www.rba.gov.au/education/resources/explainers/exchange-rates-and-their-measurement.html
  2. https://www.bis.org/statistics/rpfx25_fx.htm
  3. https://www.bis.org/publications/202509-commentary-otc-derivatives
  4. https://www.cmegroup.com/education/courses/introduction-to-fx/importance-of-fx-futures-pricing-and-basis
  5. https://www.cmegroup.com/education/demos-and-tutorials/cme-liquidity-tool-user-guide
  6. https://www.ecb.europa.eu/stats/policy_and_exchange_rates/euro_reference_exchange_rates/html/index.en.html