Read the currency pair
An exchange rate says how much of one currency buys one unit of another, and it always involves a pair. The pair is written as base and quote: in USD/EUR the base is the US dollar, the quote is the euro, and a rate of 0.89566 means one US dollar buys 0.89566 euros. This calculator uses that same reading everywhere: a rate shown as "A/B" means units of B for one unit of A, so the rate always tells you how much you receive per unit you give.
The inverse of a rate is the same exchange read from the other side. If one US dollar buys 0.89566 euros, one euro buys 1 ÷ 0.89566 = 1.1165 US dollars. The page shows both and the swap button flips the pair. This matters because currencies are quoted in both directions and a rate that looks unattractive in one direction may simply be the inverse of a familiar quote.
Pick a source currency, a target currency and the amount you plan to send or spend. Everything on the page is expressed in those two currencies: fees in the source currency come off or on top of what you pay, a fee charged in the target currency comes off what the recipient receives, and the result is shown in the currency's own number of decimal places, so yen appear without decimals and dinars with three.
Reference rates and offered rates
There is no single exchange rate at a given moment. Central banks and market data providers publish reference rates, which describe where a currency traded on a given day. A bank, a card network or a transfer company then quotes you a different rate, because it builds in a margin, and often adds fees on top. The calculator's Reference mode loads a dated central-bank rate so you have an honest benchmark. Manual mode lets you type the rate you were actually offered.
Reference rates here come from the Frankfurter service, which republishes official central-bank rates. The calculator pins one named source for each pair instead of letting the service blend several. It uses the European Central Bank for pairs of the currencies the ECB publishes, and Bank Al-Maghrib only for pairs the ECB does not cover, such as the UAE dirham or the Moroccan dirham against the US dollar, when that bank publishes both. The page names the source and its date beside every rate it uses. If no single source covers the pair, it says so and suggests Manual mode instead of guessing.
A reference rate is not a quote you can transact at. It is useful because it shows how far your offered rate sits from the benchmark. In Compare mode you can enter a quoted rate for an offer and the page notes how far it is above or below the reference rate. That difference is information, not advice.
In Reference mode the date beside the rate is the source's own publication date, so read it before you rely on the figure: a rate dated several days ago describes where the currency traded then, not where a provider will price it today.
Fees deducted versus added
Fees reduce what the recipient gets, but providers apply them in two different ways, and the page lets you choose. In deduct mode, the amount you enter is the total you pay, and fees come out of it before conversion: a percentage fee and a fixed fee in your currency reduce the amount that is converted, and a fixed fee in the target currency is subtracted after. In add mode, the amount you enter is the amount converted, and the fees are paid on top, so your total cost is higher.
The formulas are plain. With amount A, a percentage fee p of the entered amount, a fixed fee fA in the source currency and fB in the target currency at rate r, deduct mode gives A × (1 − p) − fA converted, so the recipient receives (A × (1 − p) − fA) × r − fB, and you pay A. Add mode converts all of A, so the recipient receives A × r − fB, and you pay A × (1 + p) + fA. The percentage fee is always a share of the amount entered, in both modes.
Take 1,000 units at an illustrative rate of 2, a 1% fee, a fixed fee of 5 in the source currency and 3 in the target. In deduct mode 985 is converted, the recipient receives 1,967 and you pay 1,000, an effective rate of 1.967. In add mode the full 1,000 is converted, the recipient receives 1,997, and you pay 1,015, an effective rate of 1.9675. With no fees the same 1,000 would deliver 2,000. The effective net rate is what the recipient receives divided by everything you pay, which is the number to compare across providers.
The two fee modes give the same answer when every fee is zero, so the choice only matters once you enter a fee. Use deduct mode when a provider says "we take our fee from your transfer" and add mode when it says "you pay the fee on top".
Compare two offers on equal budgets
Comparing two exchange offers is harder than it looks, because they often differ in three ways at once: the rate, the percentage fee and the fixed fee. A lower fee with a worse rate can beat a higher fee with a better rate, and the answer changes with the amount. The Compare mode puts two offers side by side. For each, you choose whether to use the reference rate or a rate you were quoted, and you enter its fees.
Same budget, different fee bases
The fair comparison holds the total cost fixed. If one offer deducts fees and another adds them, the same entered amount does not cost the same, so the page also shows an equal-budget view: both offers are scaled so that each costs exactly the same total in the source currency, and the recipient amounts are directly comparable. In add mode, the budget is first reduced by the fixed fee and then divided by one plus the percentage, to find how much can be converted. With the earlier numbers, a 1,000 budget in add mode converts 985.15 and delivers 1,967.30, compared with 1,967 in deduct mode at the same cost.
A concrete case: one offer gives a rate of 1.98 with no fees, the other a rate of 2.00 with a 3% fee. For a 1,000 budget the first delivers 1,980 and the second 1,940, so the offer with the better headline rate delivers less. The page does not name a winner on unequal budgets. It shows the totals and lets you read the equal-budget table.
Compare mode also answers a question that comes up with transfer services: is a lower rate with no fee better than a better rate with a fee? The answer depends on the amount. A fixed fee weighs more on a small transfer and less on a large one, so an offer with a fixed fee can be the worse choice for a small amount and the better choice for a large one. Try the same two offers at two different amounts and watch the equal-budget table change.
Worked conversion and inverse
Suppose the reference rate for USD/EUR is 0.89566, which is the European Central Bank's reference rate on 6 November 2026, used here only as a dated example. Converting 1,000 US dollars with no fees gives 1,000 × 0.89566 = 895.66 euros. The inverse rate is 1.1165 dollars per euro, so converting 895.66 euros back at the inverse rate returns 1,000 dollars before fees, which is a handy sanity check on any conversion.
Add a realistic fee and the picture changes. A 1% fee deducted from the 1,000 dollars converts 990 dollars and delivers 886.70 euros, or 0.88670 euros per dollar spent. The fee cost the recipient 8.96 euros. If a fixed fee of 5 dollars is also charged, 985 dollars is converted. The point of the effective net rate is that these costs show up in one number.
When you swap the currencies the page loads the reciprocal pair, and it resets the fee fields to zero with a notice, because a fee of 5 in the old source currency is not 5 in the new one. In Manual mode, swapping inverts the rate you typed and resets the fees.
Percentage fees and fixed fees cross over at a break-even amount. A 3% fee and a fixed fee of 15 cost the same at 15 ÷ 0.03 = 500 units. At 200 units the fixed fee is 7.5% of the amount, and the recipient gets 370 against 388 with the percentage fee. At 1,000 units the fixed fee is only 1.5%, and the recipient gets 1,970 against 1,940. This is why a small transfer and a large one can point to different providers, and why the effective net rate, not the headline fee, is the number to compare.
Dates, weekends and unavailable currencies
Central-bank reference rates are published for working days. A rate shown on a Saturday or a holiday is normally the last published one, and the page always displays the date the source published it, never today's date. The calculator also checks the date: a rate dated after today in UTC is rejected as invalid, and a rate more than four calendar days old is not used unless you tick the box to accept an older rate. If a rate is old you will see its date in the message beside the rate and in the CSV.
Not every currency is covered. The currency lists come from the sources themselves, and a currency that has been discontinued or has no recent data is left out. The calculator will not invent a rate or switch to a different source behind your back: if the pair is not covered by one source on one date, it says so. In that case, switch to Manual mode, type the currency codes and a rate from a source you trust, and the fee calculation works the same way. Manual mode treats currency codes as labels, so it does not check them against any list.
Requests for rates carry only the two currency codes and the source name. The amount you enter, your fees and the result stay in your browser. A rate is kept in memory for ten minutes so repeated changes do not repeatedly query the service, and if the service is slow or unreachable the page says so and offers a retry.
On a Monday morning the newest published rate is often Friday's, which is three days old and still inside the four-day window. After a long holiday weekend the window can pass, and the page then asks you to accept an older rate. That is deliberate. A date older than the window can mean a source skipped a publication, and you should decide whether the rate is good enough for your purpose instead of having the calculator quietly use it.
What this tool excludes
The calculator covers fiat currencies only. It does not convert cryptocurrencies, show intraday trading quotes or pip values, forecast exchange rates or recommend a provider. It does not know a provider's hidden margin; it only reflects the rate and fees you enter. Taxes on currency gains, ATM operator charges and card network surcharges that are not in your fees are not included.
It also does not predict how a rate may move before you send the money. A transfer that settles days after you quote it can arrive at a different rate unless the provider locks the rate, so treat the calculation as a snapshot. The tool treats a rate as one number for any amount, while some providers quote different rates for different transaction sizes or for cash, card and bank-transfer channels. You can model that by entering each quoted rate as its own offer in Compare mode.
Currency codes in Manual mode are labels, which means the page cannot warn you if a rate looks implausible for the pair. Check a manual rate against a source you trust before you rely on the result.
How to use the result
Use Reference mode to see the benchmark and your cost at a glance, and Compare mode before you choose between two providers for a transfer or a card. Pair it with the percentage calculator to turn a percentage fee into an amount, the unit price calculator to compare costs per unit when shopping abroad, and the budget calculator to plan travel spending.
A practical routine: first load the reference rate for your pair to see the benchmark and its date. Then enter the rate and fees each provider quoted as an offer, using the same amount for each, and read the equal-budget table, which removes the difference between providers that deduct fees and providers that add them. Finally, download the CSV if you want to keep the working. The file records the source and date of the rate, the fee mode and each offer's ledger, so a later reader can see exactly what was assumed.
If the cheapest offer is only a few currency units better, weigh speed, delivery method and reliability too. The calculator measures cost, not service.
Currency calculator questions
Is the reference rate the rate my bank will give me?
No. A reference rate is a benchmark published by a central bank. Banks, cards and transfer services quote their own rates, usually with a margin, plus fees. Enter your quoted rate in Manual or Compare mode to see the real cost.
What does the date next to the rate mean?
It is the date the source published the rate, which can be earlier than today, for example over a weekend or holiday. The calculator rejects dates after today and will not use a rate more than four days old unless you choose to.
Which fees does the calculator include?
Only the ones you enter: a percentage fee, a fixed fee in the source currency and a fixed fee in the target currency. It does not guess a bank's margin or hidden charges.
What happens when I swap the currencies?
In Reference mode the reciprocal pair is loaded. In Manual mode the rate you typed is inverted. In both cases the fee fields reset to zero, because fees in the old currencies do not carry over.
Can I use my own exchange rate?
Yes. Choose Manual mode and type the rate as units of the target currency per one unit of the source currency. In Compare mode each offer can use the reference rate or a rate you were quoted.
What if my currency is missing?
The sources do not cover every currency. Use Manual mode with a rate you have verified from a source you trust and type the currency codes as labels.