We present the fabrication and characterization of helical nanobelt force sensors. These self-sensing force sensors are based on the giant piezoresistivity of helical nanobelts. The three-dimensional helical nanobelts are self-formed from 27 nm-thick n-type InGaAs/GaAs bilayers using rolled-up techniques, and assembled onto electrodes on a micropipette using nanorobotic manipulations. The helical nanobelt force sensors can be calibrated using a calibrated atomic force microscope cantilever system under scanning electron microscope. Thanks to their giant piezoresistance coefficient (515 × 10−10 Pa−1), low stiffness (0.03125 N/m), large-displacement capability (∼10 μm), and good fatigue resistance, they are well suited to function as stand-alone, compact (∼20 μm without the plug-in support), light (∼5 g including the plug-in support), versatile and large range (∼μN) and high resolution (∼nN) force sensors.