The coordinates and the total organic carbon content in compost were correlated. Two particle sizes of 0.5 and 2 mm were obtained in the compost samples; the surface color was analyzed with a colorimeter and the total organic carbon content by spectrophotometry at 588.9 nm. The results indicate that all chromaticity values were significantly affected ( p < 0.001) by particle size. Chromaticity values a ∗ , b ∗ , C ∗ , and h ° showed significantly strong Pearson correlations ( r > 0.95). The coordinates a ∗ ( r = − 0 .992 ) and b ∗ ( r = 0 .968 ) have the potential to be used in estimating the total organic carbon concentration in the compost samples analyzed.