I am new to trading so my question might seem obvious or stupid to some but here goes.

Exchanges often quote crypto pairs in a specific order, i.e. ETH/BTC but not very often (if at all) BTC/ETH. Also XRP/BTC but not BTC/XRP.

What if someone wants to buy BTC by selling XRP or ETC. Is it possible? If yes, how is that value calculated?

e.g. looking at ETH/BTC on Binance today the value is $8,101.82. What if I want to buy BTC from ETH (i.e. BTC/ETH), how do we calculate that value given the prices an exchange gives on ETH/BTC?

Thank you.

  • 2
    It's the reciprocal, 1/price.
    – Eliyahu
    Mar 26, 2018 at 13:25
  • If one dollar buys 8 bananas, how much does each banana cost? Mar 26, 2018 at 14:01
  • Hey guys thank you for replying but it is not just the reciprocal because the reciprocal would not be in $ but rather than in the units of the denominator coin. Perhaps I should be a bit more explicit on what I was after. I apologise for that. Read my reply to anion below.
    – chara
    Mar 27, 2018 at 14:42

1 Answer 1


whether an exchange offers the Pair ABC/DEF or DEF/ABC depends on the readability of the values. so most exchanges have the same pair-orders. you can see that effect at https://coinmarketcap.com/currencies/ethereum/#markets if you search for "ETH/BTC" and if you search for "BTC/ETH". but you can always trade in both directions. back to your example "What if someone wants to buy BTC by selling XRP or ETC. Is it possible?" yes. let's say you are trading on the ETH/BTC market: the statement "i buy btc" is equal to "i sell eth". (and the opposite statements would be "i buy eth" and "i sell btc" which is also possible on every ETH/BTC-market).

"how do we calculate that value given the prices an exchange gives on ETH/BTC?" like Eliyahu pointed out the value is simply the reciprocal of the price but this value will rarely be displayed. look at BTC/USDT for example: current price is $8101. no one wants the pair USDT/BTC because the price would be 0.0001234415BTC (1/8101 BTC) which is probably very unfamiliar for the most users.

  • Perhaps I should be a bit more specific. It is obvious that it would be the reciprocal, but the reciprocal as you quite rightly mention would be measured in BTC and not $. However, on coinmarketcap.com all prices are in $. So i guess what I was after is the pure exchange rate between the coins without converting them back to $. Is there a table on coinmarketcap I am missing? Does one need to use the prices in $ and divide them up to come up with the pure exchange rate between two coins or is there a table somewhere? Thank you.
    – chara
    Mar 27, 2018 at 14:38
  • coinmarketcap has afaik no table where they show the real exchange rate between two coins. when you click at the exchange-rate of two coins you will be redirected to the exchange where you can see the exchange-rate. coinmarketcap reads the prices at the exchanges and calculate the resulting usd-price (with the price of BTC/USD-pair i guess). so if coinmarketcap says for example "price of ETH/BTC: $462 at Binance" this does mean "you must currently pay bitcoins worth of 462usd to buy 1eth at binance".
    – anion
    Mar 27, 2018 at 14:55

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