Lot Library (lot_lib.mqh)

Related: standard library - another powerful library for MetaTrader 4 traders.

Deciding on the optimal lot size for each trade is a critical aspect of trading. The lot_lib.mqh library offers a solution to this challenge by providing various lot size calculation algorithms.

Also recommended: AlgLib: Numerical Analysis Library for MetaTrader - similar library with strong performance on MetaTrader 4.

Usage:

- Download lot_lib.mqh to the Metatrader 4\experts\include folder.
- Add the following lines to your EA:
- Replace the variable that defines the lot size (e.g., 'lot' or 'lots') with the lot() function when placing orders.
- Compile the EA and use it.

Note: For managing multiple open positions, assign the required values to the lotlib_prevlots and lotlib_prevprofit variables before opening a new position. Determine the appropriate values based on the last closed or opened position.

External Variables:

- lotsizevariant: Selects the lot size calculation algorithm (see below for options).
- startlot: Initial lot size (used in lotsizevariant 0-5).
- addlot: Lot size increment (used in lotsizevariant 1-4).
- klot: Increment ratio (used in lotsizevariant 3-4).
- maxrisk: Percentage of the deposit that can be risked (used in lotsizevariant 5-7, 11-17, 31-37).
- trueprofitpoints: Profit threshold (in points) to distinguish between profitable and unprofitable positions (used in lotsizevariant 1-4).
- balanceuse: Percentage of the balance to be used by the EA (used in lotsizevariant 5-7, 11-17, 31-37).

Possible values of lotsizevariant:

0: Fixed lot size defined by the startlot variable.
1: Increase or decrease lot size based on the profitability of the previous position (profit > trueprofitpoints).
2: Increase lot size if the previous position was unprofitable; otherwise, set to startlot.
3: Increase lot size by a factor of addlot if the previous position was unprofitable; otherwise, set to startlot.
4: Increase lot size by a factor of addlot if the previous position was unprofitable; otherwise, set to startlot.
5: Lot size is selected to limit the maximum loss to maxrisk percent of the deposit if the stop loss is triggered.
6: Lot size is a percentage of the balance, controlled by maxrisk. E.g., for EURUSD, a balance of 1000 and maxrisk=10 will open 0.1 lot.
7: Lot size is calculated as '1 percent of balance' divided by the average price movement in the last 20 bars, multiplied by 0.4.
11-17: Variants 1-7 with a maximum loss limit of maxrisk percent of the balance.
21-27: Variants 1-7 with a non-decreasing lot size.
31-37: Variants 1-7 with a maximum loss limit and non-decreasing lot size.
100-128: All variants in sequence for optimization.

Pre-configuration (if needed, modify the code):

Example of usage results:

I integrated the library into the MACD sample with stop loss and tested it on the EURUSD symbol, H1 timeframe, from 01.01.2022 to 01.08.2026, using all ticks modeling with 90% quality. The figures below show randomly selected results without optimization. The first figure demonstrates fixed lot size.

You may also like: Simple Unit Test Include Library for MQL4 - excellent alternative for library users on MetaTrader 4.

extern double takeprofit = 50;
extern double stoploss = 50;
extern double lots = 0.1;
extern double trailingstop = 30;
extern double macdopenlevel=3;
extern double macdcloselevel=2;
extern double matrendperiod=26;
#include <lot_lib.mqh>
int init()
{

.......

• 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.