diff --git a/bilby/core/prior/dict.py b/bilby/core/prior/dict.py
index 97c61322509e404d437b69b61f0358a1d1442d75..732bcf149677037557c3b5b6cf055cc65c228cc1 100644
--- a/bilby/core/prior/dict.py
+++ b/bilby/core/prior/dict.py
@@ -410,14 +410,7 @@ class PriorDict(dict):
         prob = np.product([self[key].prob(sample[key])
                            for key in sample], **kwargs)
 
-        ratio = 1
-        outsample = self.conversion_function(sample)
-        # Check if there is a constraint in sample/outsample
-        if (np.any(isinstance([self[key] for key in sample.keys()], Constraint)) or
-                np.any(isinstance([self[key] for key in outsample.keys()], Constraint))):
-            # If constraint exists in keys, caclulate the cached normalization constant
-            ratio = self.normalize_constraint_factor(sample.keys())
-
+        ratio = self.normalize_constraint_factor(sample.keys())
         if np.all(prob == 0.):
             return prob
         else:
@@ -451,14 +444,7 @@ class PriorDict(dict):
         ln_prob = np.sum([self[key].ln_prob(sample[key])
                           for key in sample], axis=axis)
 
-        ratio = 1
-        outsample = self.conversion_function(sample)
-        # Check if there is a constraint in sample/outsample
-        if (np.any(isinstance([self[key] for key in sample.keys()], Constraint)) or
-                np.any(isinstance([self[key] for key in outsample.keys()], Constraint))):
-            # If constraint exists in keys, caclulate the cached normalization constant
-            ratio = self.normalize_constraint_factor(sample.keys())
-
+        ratio = self.normalize_constraint_factor(sample.keys())
         if np.all(np.isinf(ln_prob)):
             return ln_prob
         else: