diff --git a/corems/mass_spectrum/calc/Calibration.py b/corems/mass_spectrum/calc/Calibration.py
index ea9203622..0bb9961a6 100644
--- a/corems/mass_spectrum/calc/Calibration.py
+++ b/corems/mass_spectrum/calc/Calibration.py
@@ -65,7 +65,7 @@ def __init__(self, mass_spectrum, ref_masslist, mzsegment=None):
 
         # define reference mass list - bruker .ref format
         self.ref_mass_list_path = ref_masslist
-        if self.mass_spectrum.percentile_assigned(mute_output=True)[0] != 0:
+        if self.mass_spectrum.percentage_assigned(mute_output=True)[0] != 0:
             warnings.warn(
                 "Warning: calibrating spectra which have already been assigned may yield erroneous results"
             )