Provided is a method and system for correcting key input when a key button which a user intends to input and its neighbor buttons are simultaneously pressed on a small-size keyboard. For information input, simultaneous activation by the operator of a combination of keys of a keyboard is performed, wherein each of possibility for simultaneous activation of the combination of keys is associated with an individual code generated at simultaneous activation of this combination of keys. The generated code is loaded into the adaptive code conversion unit converting this individual input code into the most probable output code, which is visualized on a display after processing by the device processor for selection of the required symbol and confirmation of the selection.