Figure 1: C-weighted app-based measurements were compared to C-weighted measurements made using a calibrated Type 1 sound level meter (SLM). In the C-weighted condition, SoundMeter measurements were typically within 3 dB of the SLM measurements across frequency and level conditions. For twoadditional apps, dB volume and advanced decibel, C-weighted level measurements were within 5 dB for most frequency by level combinations. The exceptions to this were at sound levels at and above 85 dBC at 2 kHz, where sound levels measurements were 7-8 dB lower than that measured using the calibrated Type 1 SLM. The other apps, SPLnFFT and SPL, reported levels that were approximately 8-10 dB elevated relative to the SLM across conditions. Nonlinear errors were observed at presentation levels above 85 dBC for dB volume, advanced decibel, and SPL apps. Data are mean ± standard deviation