Lot Sizing For Non Account Currencies

I was wondering if anyone would be kind enough to help with my lot size calculations. I have all the code working fine when the base currency is the same as the account currency

1 I'm really struggling to understand what to do when the base currency isn't the same. I have looked in mql and general Forex info sites but just can't seem to understand it. Can anyone direct me to a good explanation? I know that tickvalue can be obtained but many people say it isn't reliable. Im basically trying to calculate it manually.

2 Once I have the calculations I was intending to write code with a logic like below

 if (base currency != account currency) 
do conversion

Is that how this is normally approached? I am trying to keep the ea as universal as possible by not using tickvalue and using logic like above.

Thanks in advance for any help anyone can offer

William Roeder  

Risk depends on your initial stop loss, lot size, and the value of the symbol. It does not depend on margin and leverage. No SL means you have infinite risk. Never risk more than a small percentage of your trading funds, certainly less than 2% per trade, 6% total.

  1. You place the stop where it needs to be — where the reason for the trade is no longer valid. E.g. trading a support bounce the stop goes below the support.

  2. AccountBalance * percent/100 = RISK = OrderLots * (|OrderOpenPrice - OrderStopLoss| * DeltaPerLot + CommissionPerLot) (Note OOP-OSL includes the spread, and DeltaPerLot is usually around $10/pip but it takes account of the exchange rates of the pair vs. your account currency.)

  3. Do NOT use TickValue by itself - DeltaPerLot and verify that MODE_TICKVALUE is returning a value in your deposit currency, as promised by the documentation, or whether it is returning a value in the instrument's base currency.
              MODE_TICKVALUE is not reliable on non-fx instruments with many brokers - MQL4 programming forum (2017.10.10)
              Is there an universal solution for Tick value? - Currency Pairs - General - MQL5 programming forum (2018.02.11)
              Lot value calculation off by a factor of 100 - MQL5 programming forum (2019.07.19)

  4. You must normalize lots properly and check against min and max.

  5. You must also check FreeMargin to avoid stop out

Most pairs are worth about $10 per PIP. A $5 risk with a (very small) 5 PIP SL is $5/$10/5 or 0.1 Lots maximum.