Graphene is considered an excellent material for biomedical applications because of its outstanding antimicrobial performance. However, the high synthesis cost and complexity make it difficult to apply this material in numerous fields. This research focuses on synthesizing graphene nanoparticles (NPs) cost-effectively and simply. Cost-effective chemicals were used here for synthesizing graphene NPs. A simple and easy technique has been followed throughout the process. The synthesized graphene NPs were characterized by ultraviolet–visible (UV) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy-dispersive X-ray (EDX) and antimicrobial analyses. TEM analysis revealed the size and structure of nanosized graphene NPs. Excellent antimicrobial properties 99.99% bacterial inhibition against gram-negative bacterium E. coli have been obtained. The findings indicate the potential applications in different biomedical sectors for their improved antimicrobial properties.