KC's formula App relates to civil engineering and instrumentation. More specifically by installing this app, your android device will act like a portable and mini electronic device to calculate steel rod length in civil construction. This App is based on the KC's formula invented by Professor Karam Chand Gupta of Chandigarh University, India. This is the first time that such an app launched that can calculate quantity of steel bar placed in mesh form in circular, slab or dome. Abstract - When the steel reinforcement is placed in mesh form in a circular concrete slab at base or spherical dome at the top in over head service reservoir or any other structure, it is difficult to estimate/measure the total quantity of steel that would be needed or have been placed. For the purpose of calculating the total length of the steel bars, at present, the practice is – the length of each bar is measured and then added up. This is tiresome and time consuming process. I have derived a mathematical formula with the help of which we can calculate in one line the total quantity of steel that will be needed in a circular slab or spherical dome. This will not only make the process easy and time saving but also avoids error in making entries and calculations.