Abstract In view of the incompleteness of the existing component-type borehole strainmeters and the future development of borehole strainmeters, we theoretically derive generalized formulas for surface strain, north-directional differential strain, and north-directional shear strain for the n≥3-component horizontally equally spaced borehole strain observation scheme. We qualitatively evaluate their accuracy self-verification capabilities. If only the accuracy self-verification of areal strain observation is considered, the existing four-component borehole strainmeter in China is the best solution; if the comprehensive self-verification of observation accuracy is considered, i.e., the accuracy self-verification of both areal strain and shear strain, then the six-component is the best solution. For the six-component scheme, we give formulas for accuracy self-verification of areal strain and shear strain.