Improving paper characteristics through natural and cost-effective fillers is a massive issue in the paper industry. In the process of manufacturing paper, inorganic and organic fillers are utilized. Organic fillers are only appropriate for specific applications, and their expensive cost has limited their use. Here, various concentrations of sugarcane press mud (SPM) waste were applied to obtain pure calcium oxide nanoparticles (CaONPs) after the calcination to use as a potential filler in the papermaking by mixing the CaONPs at various ratios (5, 10, 15, and 20%), and paper properties have been investigated. Transmission electron microscopy (TEM), selected area electron diffraction (SAED), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDX) were utilized to characterize the CaONPs produced. The finding reveals that the influence of nano CaO fillers filled at different ratios (5, 10, 15