diff --git a/impedance/models/circuits/circuits.py b/impedance/models/circuits/circuits.py
index b670d19..1fcb1e0 100644
--- a/impedance/models/circuits/circuits.py
+++ b/impedance/models/circuits/circuits.py
@@ -133,7 +133,11 @@ def predict(self, frequencies, use_initial=False):
         impedance: ndarray of dtype 'complex128'
             Predicted impedance at each frequency
         """
-        frequencies = np.array(frequencies, dtype=float)
+        frequencies = (
+            np.array([frequencies], dtype=float)
+            if isinstance(frequencies, float)
+            else np.array(frequencies, dtype=float)
+        )
 
         if self._is_fit() and not use_initial:
             return eval(buildCircuit(self.circuit, frequencies,