Every few months you buy euros out of your forint salary: for a holiday, or just so not everything sits in one currency. Now the euro is somewhere else than when you bought it, and you can't tell whether you're up or down, or by how much.
In short: add up the forints you paid for your euros and divide by the euros you got: that's your average purchase rate. On the euros you still hold, the gain or loss is (today's rate − average purchase rate) × euros left, but only on paper until you spend them or change them back. On the euros you spent it is realised: the difference between that day's rate and your average, times the amount spent.
- Note the euros and the forints paid for every purchase
- Average purchase rate = total forints ÷ total euros
- What you hold: (today's rate − average) × euros
- What you spent: (that day's rate − average) × euros spent
Which rate to use
- For purchases, what you actually paid: the forint amount on your bank statement, fees included. That is your cost. The bank's selling rate and the fee are in it, so the result shows the real cost too.
- For today, an official reference rate: the ECB's [1], or your central bank's (MNB [2], BNR [3]), always from the same source. To know what you'd get if you changed the euros back today, look at your bank's buying rate instead: it's a little lower.
How the rates differ, and why you stick to one source: net worth in multiple currencies.
An example: four euro purchases and a holiday
A made-up but realistic case with real rates: you live in Hungary, and in 2026 you buy €500 four times, spend €500 on a holiday in Croatia in August, and check where you stand in October. To keep it simple, every purchase is at that day's ECB reference rate [1]; your bank would have sold you the euros for a little more.
| Euros | Forints per euro | You paid | |
|---|---|---|---|
| 15 January | €500 | 385.65 | 192,825 Ft |
| 16 March | €500 | 390.23 | 195,115 Ft |
| 15 May | €500 | 359.78 | 179,890 Ft |
| 15 July | €500 | 359.65 | 179,825 Ft |
| Total | €2,000 | average 373.83 | 747,655 Ft |
Your average purchase rate is 747,655 Ft ÷ €2,000 = 373.83 Ft. That's what one euro cost you on average.
- 12 August, holiday: you spend €500. That day one euro was 364.10 Ft [1], so the euros you spent were worth 182,050 Ft but cost you 186,914 Ft at your average rate. Realised loss: 4,864 Ft. The average purchase rate doesn't change: each euro you have left still cost 373.83 Ft.
- 22 October, today: you have €1,500 left. The ECB puts one euro at 366.43 Ft [1], so those euros are worth 549,645 Ft but cost you 560,741 Ft. On paper, a loss of 11,096 Ft.
−15,960 Ft
The two parts always add up to the whole: what you got back (a 182,050 Ft holiday, plus 549,645 Ft that your remaining euros are worth today) minus what you paid (747,655 Ft) is −15,960 Ft. The paper part can look different tomorrow: if the euro climbs back above 373.83 Ft, it's gone.
The loss doesn't mean buying euros was a mistake: you needed them for the holiday anyway. It only shows that the forint got stronger since you bought. If you counted your money in euros, there would be no loss at all: a currency gain or loss is always measured against the currency you count in.
What this leaves out
- Average or order. Here the euros you spent cost your average rate. Another method spends the oldest euros first (FIFO), which splits realised and paper gains differently. Once every euro is spent, both methods give the same total.
- Fees and the bank's rate. If you count with the forint amounts on your statement, they're included. If you count with reference rates, like the example, your real loss is a little bigger.
- Interest isn't a currency gain. If your euros earn interest, count it separately.
- This is tracking, not a tax return. Whether a currency gain is taxed, and how to calculate it for tax, is a separate question. Check with your tax authority (NAV in Hungary, ANAF in Romania) or a tax adviser.
Try it with your own numbers
The calculator below starts with the example above. Replace it with your own: for each purchase, the euros you got and the forints you paid, as on your bank statement; for spending, the euros and that day's rate. The ECB button fills in today's rate [1]. Your entries stay in your browser; it is also on its own page as the average exchange rate calculator.
Use an official reference rate, always from the same source. To see what your bank would give you back, use its buying rate.
Your average rate and result
- You paid in total
- Ft 747,655
- You still hold
- €1,500
- What it cost you
- Ft 560,741
Average purchase rate
373.83 HUF for 1 EUR
- On what you spent (realised)
- -Ft 4,864
- On what you hold (on paper)
- -Ft 11,096
- Total gain or loss
- -Ft 15,960
Average purchase rate = what the money you hold cost ÷ how much you hold. Each purchase moves it; spending doesn't. Realised = amount spent × (that day's rate − average). On paper = amount held × (today's rate − average).
Your entries stay in this browser and are not saved. The ECB button sends only today's date and the two currency codes to our server, which asks the ECB. For tracking, not for a tax return.
For a period, say how much of your net worth's growth from January to October came from saving and how much from the rate, use the currency gain/loss calculator.
Do this today
Open your bank statement and find this year's euro purchases. Write them one under the other: date, euros, forints paid. At the bottom: total forints ÷ total euros. That's your average purchase rate. If today's rate is above it, you're up on the euros you still hold; if it's below, you're down.
If you'd rather not keep it by hand: in the Volora app each foreign-currency wallet remembers the average rate you bought its money at, and the Insights tab shows, per currency, how much you've gained or lost on the rate since, and what share of your net worth that is. Rates refresh every 30 days on the free plan, daily on Premium. More on tracking net worth in more than one currency.