PAcalculate is a free utility tool designed by Doctor ProAudio for pro-audio and lighting professionals. It is a very light (~1MB) application that works offline and uses no data bandwidth. The app consists of more than 26 calculators for pro-audio sound reinforcement and lighting, as well as reference info and utilities.

The app is an excellent tool for people dealing with PA, sound reinforcement, sound systems, electroacoustics, pro-audio, and lighting. It includes over 42 calculations spread across 26 calculators, such as SPL (sound pressure level), air absorption attenuation, ceiling speaker coverage, audio frequency wavelength, line array transition distance, limiter threshold, amplifier gain, speaker cable, electrical and musical calculators, and much more.

PAcalculate also offers reference info, including pinouts, proaudio, and lighting graphs. Additionally, it has utilities such as an inclinometer and flashlight (needs camera permission that can be later revoked in phone settings). The app is available for Android, iOS (iPhone/iPad), and WindowsPhone versions.

In conclusion, PAcalculate is a super handy tool for pro-audio and lighting professionals that offers accurate and relevant calculations, reference info, and utilities. It is a must-have app for sound reinforcement and lighting professionals.