This book was carried out with a view to determine applicable Runoff estimation by using software in SCS Curve Number Method. Which could be usefull in designing and development of software. As such this book should prove interest both to undergraduates studying as well as postgraduates in soil and water conservation engineering. Thus, the selection of CN from the table based on field condition requires very accuracy. To overcome, all this difficulty and to accurately estimate the surface runoff a web base tool was developed by using the open source software PHP and JQuery. This web base tool is based on one of the most popular methods of estimation of runoff namely, SCS Curve Number method, one can easily estimate the runoff of the area under consideration. All the basic input parameters involved in the runoff estimation namely AMC, Initial Loss, Rainfall depth, Number of watershed, Hydrologic Soil Group, Land Use/Cover Type, etc. are accommodated in single screen itself. By submitting the input parameters, the CN value appears in {} (Curly Braces), which finally gives the output in the form of runoff in centimeters.