Universal Pip Value and Dynamic Lot Calculator Class for MQL5 - library for MetaTrader 5

CRiskCalculator is an object-oriented MQL5 header library designed to handle risk management and volume calculations for Expert Advisors and trading tools . It calculates monetary pip values and precise lot sizes based on a specific account risk amount and Stop Loss distance in pips .

A common issue in automated trading is calculating position sizing on cross-currency pairs (for example, trading GBPJPY on an EUR-denominated account) . This class addresses that challenge by combining native MetaTrader 5 symbol properties with a fallback conversion system for cross-currency pairs .

Key Features

• Dual-Engine Calculation: Uses native broker properties ( SYMBOL_TRADE_TICK_VALUE and SYMBOL_TRADE_TICK_SIZE ) as the primary calculation method . If those parameters are unavailable or uninitialized by the broker, it automatically falls back to manual base/quote currency extraction and conversion rate queries .

• Broker Parameter Normalization: Automatically clamps calculated volumes between SYMBOL_VOLUME_MIN and SYMBOL_VOLUME_MAX , and aligns them to SYMBOL_VOLUME_STEP to avoid broker rejection errors (such as TRADE_RETCODE_INVALID_VOLUME ) .

• Clean OOP Design: Encapsulated inside the CRiskCalculator class with no global scope clutter, making it easy to drop into existing EA projects or custom indicators .

• Self-Configuring: Automatically detects the current account base currency ( ACCOUNT_CURRENCY ) upon initialization .

Integration Example

To use this class in your Expert Advisor or script, place CRiskCalculator.mqh inside your MQL5/Include/ directory and instantiate the object :

#include <CRiskCalculator.mqh>

// Helper function to render a high-contrast panel on the chart
void DrawChartPanel(const string &lines[])
  {
   int x = 20, y = 30;
   int width = 280, lineHeight = 18;
   int height = (ArraySize(lines) * lineHeight) + 20;

   // 1. Create Background Box (Visible on white, black, or custom charts)
   string bgName = "RiskCalc_BG";
   if(ObjectFind(0, bgName) < 0)
      ObjectCreate(0, bgName, OBJ_RECTANGLE_LABEL, 0, 0, 0);

   ObjectSetInteger(0, bgName, OBJPROP_CORNER, CORNER_LEFT_UPPER);
   ObjectSetInteger(0, bgName, OBJPROP_XDISTANCE, x);
   ObjectSetInteger(0, bgName, OBJPROP_YDISTANCE, y);
   ObjectSetInteger(0, bgName, OBJPROP_XSIZE, width);
   ObjectSetInteger(0, bgName, OBJPROP_YSIZE, height);
   ObjectSetInteger(0, bgName, OBJPROP_BGCOLOR, clrDarkSlateGray);
   ObjectSetInteger(0, bgName, OBJPROP_BORDER_COLOR, clrDodgerBlue);
   ObjectSetInteger(0, bgName, OBJPROP_BORDER_TYPE, BORDER_FLAT);
   ObjectSetInteger(0, bgName, OBJPROP_SELECTABLE, false);

   // 2. Render Text Lines inside the panel
   for(int i = 0; i < ArraySize(lines); i++)
     {
      string lblName = "RiskCalc_Lbl_" + IntegerToString(i);
      if(ObjectFind(0, lblName) < 0)
         ObjectCreate(0, lblName, OBJ_LABEL, 0, 0, 0);

      ObjectSetInteger(0, lblName, OBJPROP_CORNER, CORNER_LEFT_UPPER);
      ObjectSetInteger(0, lblName, OBJPROP_XDISTANCE, x + 12);
      ObjectSetInteger(0, lblName, OBJPROP_YDISTANCE, y + 10 + (i * lineHeight));
      ObjectSetString(0, lblName, OBJPROP_TEXT, lines[i]);
      ObjectSetString(0, lblName, OBJPROP_FONT, "Segoe UI");
      ObjectSetInteger(0, lblName, OBJPROP_FONTSIZE, 9);
      ObjectSetInteger(0, lblName, OBJPROP_COLOR, (i == 0) ? clrYellow : clrWhite);
      ObjectSetInteger(0, lblName, OBJPROP_SELECTABLE, false);
     }

   ChartRedraw(0);
  }

void OnStart()
  {
   // Instantiate the risk calculator
   CRiskCalculator riskCalc;

   string symbol     = _Symbol;
   double riskAmount = 100.0; // Target risk in account currency
   double slPips     = 25.0;  // Stop Loss distance in pips

   // Calculate parameters
   double lotSize      = riskCalc.CalculateLotSize(symbol, riskAmount, slPips);
   double pipValPerLot = riskCalc.GetPipValuePerLot(symbol);

   // Prepare output lines
   string info[6];
   info[0] = "=== RISK & POSITION CALCULATOR ===";
   info[1] = "Symbol: " + symbol;
   info[2] = "Account Currency: " + AccountInfoString(ACCOUNT_CURRENCY);
   info[3] = "Target Risk: $" + DoubleToString(riskAmount, 2);
   info[4] = "Calculated Lot Size: " + DoubleToString(lotSize, 2) + " lots";
   info[5] = "Pip Value (1 Lot): " + DoubleToString(pipValPerLot, 2);

   // Display GUI panel on chart
   DrawChartPanel(info);
  }

Class Reference

Need Custom Development or EA Integration?

If you need custom Expert Advisors, custom indicators, or advanced risk management systems built for MetaTrader 5, feel free to reach out directly via MQL5 Freelance:

👉 Romeo Luvisotto — MQL5 Developer Profile & Freelance Services