Purpose: Almost all smartphone-based personal sound amplification applications (PSAPs) do not provide amplification specifications as well as medical hearing aid (HA) products. Therefore, the main purpose of this study is to develop an HA-simulator and investigate the possible fitting range of this smartphone-based PSAP app equipped with a commercial headset, and to evaluate whether the aided outcome provides reasonable benefits for individuals with hearing loss by analyzing the Speechmap and speech intelligibility index (SII). Methods: An HA-simulator with a four-channel compression structure was developed and evaluated using a smartphone equipped with Apple EarPods. Measurement methods specified by the ANSI S3.22 were used to evaluate the electroacoustic performance of the proposed system. The Speechmap method and SII were used to check if the amplified speech for five different hearing loss configurations. These ANSI S3.22 and Speechmap measurement results were then compared with a digital HA under the same test conditions. Results: The results demonstrated that the proposed HA-simulator system provided an adequate output sound level for patients with mild-to-moderate hearing loss and a tolerable group delay for the user while providing an electroacoustic performance comparable to that of a digital HA based on ANSI S3.22 test criteria. The amplified speech signals presented by Speechmap and the corresponding SII values indicated that the proposed HA-simulator provided benefits comparable to those of medical HA. Conclusions: These results indicate that a smartphone-based HA simulator could provide suitable performance to that of a medical HA, and it potentially aid individuals with hearing loss.