There is provided a gesture-based GUI (system, method, etc.) to facilitate input of numerical data using a continuous swipe gesture. A gesture-based I/O device displays a GUI presenting a gross number and a gross number control to initially define a specific number for further defining with specificity. In response to a first gesture (hard click or pause) interacting with the gross number control, the specific number is initially defined as the gross number and a finer number control is presented to refine the specific number. In response to a continuous swipe gesture continuing from the first gesture and interacting with the finer number control, the interface further defines the specific number with finer specificity where a quantum varies in response to a direction and distance of the continuous swipe. Successive finer number controls may be also be presented to refine the specific number by continuing the swipe.