The most popular single-number quantities (SNQs) of impact sound insulation in Europe are L’n,w and L’nT,w. They are based on measurements within 1003150 Hz. Recently, it was proposed that the measurements should be extended down to 25 Hz for wooden floors, and L’nT,w+CI,25 should replace L’nT,w. The purpose of this study is to analyze which of the two SNQs, Ln,w or LnT,w+CI,25, predicts the annoyance of natural impact sounds better for wooden floors. We conducted a psychoacoustic experiment, where 52 participants rated the annoyance of 75 impact sounds. As stimuli, five types of natural impact sounds were used. They were recorded for 15 different wooden floors built in an impact sound insulation laboratory, where also their SNQs were measured. Based on correlation analysis, Ln,w explained annoyance of natural impact sounds equally well or better than Ln,w+CI,25, depending on impact sound type Therefore, based on perception, it seems to be sufficient to conduct measurements within 1003150 Hz for wooden floors and assess their sound insulation using L’nT,w or L’n,w.