# Smart Lot Calculator for MQL5

Smart Lot Calculator is an open-source MQL5 library for calculating position size according to the amount of money a trader is willing to risk.

The library uses MetaTrader 5's native `OrderCalcProfit()` function to estimate the potential loss between the entry price and the Stop Loss price in the account currency.

## Features

- Calculates volume by risk percentage
- Calculates volume by a fixed monetary risk
- Supports balance, equity and free-margin risk bases
- Uses the broker's own symbol calculation settings
- Supports buy and sell calculations
- Respects minimum and maximum volume
- Respects the symbol volume step
- Rounds volume down to avoid exceeding the selected risk
- Provides clear error messages
- Does not open or manage trades

## Repository structure

```text
Include/SmartLotCalculator.mqh
Scripts/SmartLotCalculatorExample.mq5
Docs/Usage.md
```

## Basic example

```cpp
#include "../Include/SmartLotCalculator.mqh"

void OnStart()
{
   MqlTick tick;

   if(!SymbolInfoTick(_Symbol, tick))
      return;

   double entry_price = tick.ask;
   double stop_price  = entry_price - (500 * _Point);
   string error       = "";

   double volume = CSmartLotCalculator::CalculateByRiskPercent(
      _Symbol,
      ORDER_TYPE_BUY,
      entry_price,
      stop_price,
      1.0,
      RISK_BASE_EQUITY,
      error
   );

   if(volume <= 0.0)
   {
      Print("Calculation error: ", error);
      return;
   }

   Print("Recommended volume: ", DoubleToString(volume, 2));
}
```

## Important

This project is a position-sizing reference tool. It does not guarantee profits, prevent losses or provide trading signals.

Always verify the calculated volume before trading. Symbol specifications and trading conditions can differ between brokers.

## License

MIT License.