It's much more than that actually. You won't get the required transaction fees for less confirmation time just by entering the amount.
While calculating the optimum transaction fees there are many factors which are considered in place

The number of inputs that are consumed
The type of bitcoin address
The size of the transaction
The current mempool size

All the above are some important factors and you will have to create the code in such a way that it fetches all the above data and then determine the optimum transaction fees required.