This study aims to provide a detailed guide on how to read and interpret FTIR (Fourier Transform Infrared) spectroscopy data for organic materials. The authors, Asep Bayu Dani Nandiyan, Rosi Oktiani, and Risti Ragadhita, from the Department of Chemistry at Universitas Pendidikan Indonesia, present a step-by-step method for analyzing FTIR spectra, ranging from simple to complex organic materials. The study focuses on the mid-IR spectrum, which is the most commonly used for sample analysis, and divides it into four regions: single bond, triple bond, double bond, and fingerprint regions. The authors provide specific frequency ranges for various functional groups and detailed steps for identifying absorption bands, including the identification of double bonds, aromatic compounds, and fingerprint regions. The study also includes an experimental section where LR (Lumbricus rubellus) microparticles are analyzed at different heating temperatures to demonstrate the changes in FTIR peaks and patterns, indicating the decomposition of organic components into carbon material. The results are compared with literature data, and the study concludes that the presented method can serve as a standard for students and beginners in understanding and interpreting FTIR data.This study aims to provide a detailed guide on how to read and interpret FTIR (Fourier Transform Infrared) spectroscopy data for organic materials. The authors, Asep Bayu Dani Nandiyan, Rosi Oktiani, and Risti Ragadhita, from the Department of Chemistry at Universitas Pendidikan Indonesia, present a step-by-step method for analyzing FTIR spectra, ranging from simple to complex organic materials. The study focuses on the mid-IR spectrum, which is the most commonly used for sample analysis, and divides it into four regions: single bond, triple bond, double bond, and fingerprint regions. The authors provide specific frequency ranges for various functional groups and detailed steps for identifying absorption bands, including the identification of double bonds, aromatic compounds, and fingerprint regions. The study also includes an experimental section where LR (Lumbricus rubellus) microparticles are analyzed at different heating temperatures to demonstrate the changes in FTIR peaks and patterns, indicating the decomposition of organic components into carbon material. The results are compared with literature data, and the study concludes that the presented method can serve as a standard for students and beginners in understanding and interpreting FTIR data.