diff --git a/doc/tespy_modules/characteristics.rst b/doc/tespy_modules/characteristics.rst
index 62cacf3a3..8308cadd7 100644
--- a/doc/tespy_modules/characteristics.rst
+++ b/doc/tespy_modules/characteristics.rst
@@ -44,7 +44,7 @@ a vector for each dimension (y, z1 and z2).
     \vec{z1} = \vec{z1_0} + \frac{x-x_0}{x_1-x_0} \cdot \left(\vec{z1_1}-
     \vec{z1_0} \right)
 
-    \vec{z2} = \vec{z2_0} + \frac{x-x_0}{x1-x_0} \cdot \left(\vec{z2_1}-
+    \vec{z2} = \vec{z2_0} + \frac{x-x_0}{x_1-x_0} \cdot \left(\vec{z2_1}-
     \vec{z2_0}\right)
 
 Using the y value as second input dimension the corresponding z1 and z2 values
diff --git a/tespy/tools/characteristics.py b/tespy/tools/characteristics.py
index 4948d3f85..d6c47f3b4 100644
--- a/tespy/tools/characteristics.py
+++ b/tespy/tools/characteristics.py
@@ -345,7 +345,7 @@ def evaluate(self, x, y):
             \left(\vec{y_1}-\vec{y_0} \right)\\
             \vec{z1} = \vec{z1_0} + \frac{x-x_0}{x_1-x_0} \cdot
             \left(\vec{z1_1}-\vec{z1_0} \right)\\
-            \vec{z2} = \vec{z2_0} + \frac{x-x_0}{x1-x_0} \cdot
+            \vec{z2} = \vec{z2_0} + \frac{x-x_0}{x_1-x_0} \cdot
             \left(\vec{z2_1}-\vec{z2_0}\right)
 
         The index :math:`x_0` represents the lower and :math:`x_1` the