Lot Size Representing percentage of margin over balance

[Mi p]

Say I want to open a position and I want to know what lot size I would need so that the margin takes up a certain percentage of the balance. If the balance were $10000, and I wanted a margin of 6%, or $600, how to determine the lot size that I would need to accomplish this?

[Sergey Golubev]

You can search in CodeBase or in the Market to find something related to your request:

How to make a search on the forum?Market/CodeBase
https://www.mql5.com/en/forum/193510

[Sergey Golubev]

Forum on trading, automated trading systems and testing trading strategies

Support and Resistance Levels

Eleni Anna Branou, 2020.01.09 13:01

If you can't find it in the Codebase or in the Market, you can order it in Freelance.

[William Roeder]

Margin is irrevalent. Control your risk.

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 You place the stop where it needs to be — where the reason for the trade is no longer valid.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.