diff --git a/deeplc/deeplc.py b/deeplc/deeplc.py
index 147dc51..062c430 100644
--- a/deeplc/deeplc.py
+++ b/deeplc/deeplc.py
@@ -482,9 +482,9 @@ def calibration_core(self, uncal_preds, cal_dict, cal_min, cal_max):
             return np.array(cal_preds)
         if self.pygam_calibration:
             linear_model_left, spline_model, linear_model_right = cal_dict
-            y_pred_spline = spline_model.predict(uncal_preds)
-            y_pred_left = linear_model_left.predict(uncal_preds)
-            y_pred_right = linear_model_right.predict(uncal_preds)
+            y_pred_spline = spline_model.predict(uncal_preds.reshape(-1, 1))
+            y_pred_left = linear_model_left.predict(uncal_preds.reshape(-1, 1))
+            y_pred_right = linear_model_right.predict(uncal_preds.reshape(-1, 1))
 
             # Use spline model within the range of X
             within_range = (uncal_preds >= cal_min()) & (uncal_preds <= cal_max())