diff --git a/src/easyscience/Objects/Variable.py b/src/easyscience/Objects/Variable.py
index 10362ba9..3de9bef0 100644
--- a/src/easyscience/Objects/Variable.py
+++ b/src/easyscience/Objects/Variable.py
@@ -721,6 +721,14 @@ def fixed(self, value: bool):
             raise ValueError
         self._fixed = value
 
+    @property
+    def free(self) -> bool:
+        return not self.fixed
+
+    @free.setter
+    def free(self, value: bool) -> None:
+        self.fixed = not value
+
     @property
     def error(self) -> float:
         """
diff --git a/src/easyscience/Objects/new_variable/parameter.py b/src/easyscience/Objects/new_variable/parameter.py
index 26992c04..ebad24b4 100644
--- a/src/easyscience/Objects/new_variable/parameter.py
+++ b/src/easyscience/Objects/new_variable/parameter.py
@@ -301,6 +301,14 @@ def fixed(self, fixed: bool) -> None:
             raise ValueError(f'{fixed=} must be a boolean. Got {type(fixed)}')
         self._fixed = fixed
 
+    @property
+    def free(self) -> bool:
+        return not self.fixed
+
+    @free.setter
+    def free(self, value: bool) -> None:
+        self.fixed = not value
+
     @property
     def bounds(self) -> Tuple[numbers.Number, numbers.Number]:
         """