A chromatic tuner detects any of the twelve pitches in the chromatic scale and tells you which note you are closest to and by how much you are sharp or flat. This distinguishes it from a simple guitar tuner locked to six fixed strings: because it recognizes every note, it works for any instrument, any alternate tuning and any transposition. Modern software chromatic tuners capture sound through a microphone, analyze the waveform to estimate its fundamental frequency, and display the result against a reference pitch, usually A440. Web-based versions rely on the browser's audio capabilities, defined by the W3C Web Audio API specification, to access the microphone and process the signal in real time with no plugin or install. That openness lets a single page tune a guitar in DADGAD, a violin, a ukulele or a bass equally well. FretMind's chromatic tuner supports many instruments and over 25 alternate tunings, with a reference pitch adjustable from 430 to 450 Hz.