diff --git a/code/tuner/main.py b/code/tuner/main.py
index 5e26195..3ea6bbf 100644
--- a/code/tuner/main.py
+++ b/code/tuner/main.py
@@ -18,7 +18,7 @@ NOTES = "A B♭/A♯ B C D♭/C♯ D E♭/D♯ E F F♯/G♭ G A♭/G♯".split(
 # Get the note and octave using known note forumla
 def calculate_note(frequency):
     if frequency > 0:
-        note_num = round(math.log2(frequency / 440) * 12)
+        note_num = round(math.log2(frequency / A4) * 12)
         octave = math.floor(4 + note_num / 12)
         rel_note = note_num % 12
         note = NOTES[rel_note]