This indicator only is based on the MT4 Platform.
To use it, download the indicator, place it in your metatrader expert>sub folder like below:
C:\Program Files\MetaTrader - yourbroker\experts\indicators
To use it, open your MT4, scroll it on your left side bar under the Custom Indicators. Find the LotCalculator v1, click and drag it to your chart and key-in your SL and your risk (%) then it will calculate the lot size for you! Click OK after you key-in the numbers.
to download go here: http://duitdariforex.com/lotsizecalculator.php