We describe a new method for the accurate measurement of optical rotation. It is based on curve-fitting the signal of a new optical rotation polarimeter that we have recently developed. The calculated accuracy ($\sim{80}\,\,\unicode{x00B5} ^\circ $∼80µ∘), and precision ($\sim{220}\,\,\unicode{x00B5} ^\circ )$∼220µ∘) are potentially useful for various applications in the fields of biomedical devices and analytical chemistry.