Money Fixed Margin: Calculating Lot Size with Fixed Free Margin
Info
The Money Fixed Margin: Calculating Lot Size with Fixed Free Margin is a Expert Advisor for MetaTrader 5 that this tool demonstrates calculating lot size based on a fixed percentage of free margin. Input Parameters:- Stop Loss (in pips): The stop loss level for the trade.
Usage
This tool is typically used for automated trading on major forex pairs and gold.
Platform
This Expert Advisor works exclusively on MetaTrader 5 (both build 600+ and newer versions).
Setup
Place the downloaded file in MQL5/Experts folder via File ? Open Data Folder in MetaTrader 5.
How to Install and Use Money Fixed Margin: Calculating Lot Size with Fixed Free Margin
1. Installation: Open the "File" menu, select "Open Data Folder," navigate to MQL/Experts, paste your file, and restart the terminal.
2. Activation: Drag the EA from the Navigator onto a chart, ensure "Allow live trading" is checked in the Common tab, and verify the AutoTrading button is green.
3. Optimization: Right-click your chart, choose "Expert List," click "Properties" to adjust inputs, and save your preferred setup as a set file for future use.
4. Maintenance: Regularly check the "Experts" tab in the terminal window to monitor trade logs and potential execution errors.
Frequently Asked Questions
Q: Why is my EA not opening trades? A: Check the "AutoTrading" button, ensure "Allow live trading" is enabled, and verify your broker allows automated trading on your account type.
Q: Can I run multiple EAs on one chart? A: No, each chart can only host one active EA; however, you can open multiple charts for different currency pairs to run several EAs.
Q: What does the "smiley face" icon mean? A: A smiley face in the top-right corner of the chart indicates the EA is successfully running; a frowny face means it is disabled.
What this tool does
This tool demonstrates calculating lot size based on a fixed percentage of free margin.
Typical Use Case
This Expert Advisor excels in automated trading and technical analysis on MetaTrader 5.
Compatible Platform & Setup
This Expert Advisor works on MetaTrader 5. Place the file in the MQL5/Experts folder and restart the terminal.
Description & Settings
Related: Smart Money Concept Expert Advisor: Market Structure, FVG, and Pullback Trading - another powerful expert for MetaTrader 5 traders.
This tool demonstrates calculating lot size based on a fixed percentage of free margin.Also recommended: SMC Gold EA: Smart Money Concepts for XAUUSD M15 with Liquidity Sweep and Order Blocks - similar expert with strong performance on MetaTrader 5.
Input Parameters:
- Stop Loss (in pips): The stop loss level for the trade.
- % Risk: The margin for a position as a percentage of free margin.
The system simulates trading using a loop. An initial value is set for the strategy tester to warm up. A calculation based on the remainder after division by a randomly chosen number determines when the lot calculation cycle begins. This cycle calculates the lot size considering the risk per trade.
Lot Calculation Cycle (for Buy Positions):
Step One: Determine Lot Size for Open Long Position
The script first obtains the lot size for opening a long position using the `checkopenlong` method, considering the stop loss level. The calculated lot value is stored in the `check_open_long_lot` variable.
The following parameters are logged to the expert journal: stop loss, calculated lot value based on risk per trade, account balance at the time of calculation, and margin at the time of calculation.
If the calculation returns 0.0, the process exits.
Step Two: Verify Volume Capacity
Next, the script retrieves the lot value for which sufficient funds are available using the `checkvolume` method. This method takes the symbol name and the previously calculated lot size (`check_open_long_lot`) as parameters.
Step Three: Check Funds and Open Position
If the `checkvolume` method returns a value other than 0.0, the script checks if there are enough funds to open a position with the calculated lot size. If sufficient funds are available, the position is opened. Otherwise, the lot value calculated based on risk per trade and the lot value for which funds are available are logged to the expert journal.
Example of Opening a Buy Position with 10% Free Margin:
The journal logs will show the details of the calculation and trade execution, including stop loss, calculated lot size, balance, equity, free margin, and the executed trade details.
Note: When calculating the lot based on the risk of free margin, the stop loss level does not affect the lot size calculation itself.
This example was last updated in 2026.
You may also like: EA Money Management Strategy - excellent alternative for expert users on MetaTrader 5.
Source Code
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⚠ Limitations & Risk Warning
- This tool is provided for educational and testing purposes only.
- Past performance does not guarantee future results.
- Trading involves substantial risk of loss. Use on a demo account first.
- Results may vary depending on market conditions, broker, and settings.
- We recommend thorough backtesting and forward testing before using with real funds.