GuitarTunings is a fast, lightweight and completely ad-free guitar tuner built for alternate tunings. Tune in standard, drop, open, artist-specific or basically any custom tuning, then shift the entire tuning up or down by semitones with one click. It also includes a growing database of songs and artists with their guitar tunings. The tuner uses the YIN pitch detection algorithm for real-time pitch tracking, with everything running directly in the browser. No ads. No clutter. Just open and play.