# Calculation of spread arbitrage profit

I would like to know if my spread (arbitrage) calculation is correct or wrong. as an example i have bitcoins which i would like to use for the ethereum i am going to buy at market A and sell at market B.

Calculation:

2(BUY AMOUNT BTC - WITHDRAW FEE = SELL AMOUNT BTC)

3(SELL AMOUNT BTC * BID PRICE = SELL PRICE)

5((SELL PRICE + SELL PRICE * TRADE FEE) - WITHDRAW FEE) = TOTAL SELL PRICE

6(TOTAL SELL PRICE - TOTAL BUY PRICE = TOTAL PROFIT)

What i don't understand from this calculation is why is it BUY PRICE - BUY PRICE ?? and SELL PRICE + SELL PRICE ??

• I'm voting to close this question as off-topic because arbitrage profit is a financial question – renlord May 7 '18 at 22:35
• A buy is a debit (- sign) and a sell is a credit (+ sign). Also, you buy at the ask price and sell at the bid price. – Bob Baerker May 10 '18 at 17:21

I deplore the notation used, and haven't checked the overall validity.

Maybe it makes more sense to you now?

• What if we use numbers for example: 0.5 btc and a tradefee of .25% does the following calculation makes sense: 0.5 *( 1 - 0.0025) = TOTAL BUY PRICE – paul May 8 '18 at 8:35

Where did you get this formula from? Look incorrect to me.

Here is what I would calculate like:

Assume: Trade fee is 1% so, 0.01, withdrawal fee is flatrate at 0.001 btc, or whatever it is at the moment converted to USD.

``````BUY PRICE = AMOUNT * ASK + AMOUNT * ASK * TRADE FEE + WITHDRAWAL FEE
SELL PRICE = AMOUNT * BID - AMOUNT * BID * TRADE FEE

PROFIT = SELL PRICE - BUY PRICE
``````