diff --git a/Elwig/Helpers/Utils.cs b/Elwig/Helpers/Utils.cs
index 4ba5c3c..b22a959 100644
--- a/Elwig/Helpers/Utils.cs
+++ b/Elwig/Helpers/Utils.cs
@@ -173,5 +173,12 @@ namespace Elwig.Helpers {
         public static long DecToDb(decimal value, byte precision) {
             return (long)decimal.Round(value * (decimal)Math.Pow(10, precision), 0);
         }
+
+        public static int GetAge(DateOnly birthday) {
+            var today = DateTime.Today;
+            var a = (today.Year * 100 + today.Month) * 100 + today.Day;
+            var b = (birthday.Year * 100 + birthday.Month) * 100 + birthday.Day;
+            return (a - b) / 10000;
+        }
     }
 }
diff --git a/Elwig/Windows/MemberAdminWindow.xaml b/Elwig/Windows/MemberAdminWindow.xaml
index 074d0c8..f6f26f5 100644
--- a/Elwig/Windows/MemberAdminWindow.xaml
+++ b/Elwig/Windows/MemberAdminWindow.xaml
@@ -142,6 +142,9 @@
                 <TextBox x:Name="BirthdayInput" Margin="0,100,0,0" Grid.Column="1" Width="78" TextAlignment="Right" HorizontalAlignment="Left"
                          TextChanged="PartialDateInput_TextChanged" LostFocus="PartialDateInput_LostFocus"/>
 
+                <Label Content="Alter:" Margin="85,100,0,0" Grid.Column="1"/>
+                <TextBlock x:Name="Age" Text="-" Margin="119,104,0,0" Grid.Column="1" TextWrapping="NoWrap" VerticalAlignment="Top"/>
+
                 <Label Content="Adresse:" Margin="10,130,0,0"/>
                 <TextBox x:Name="AddressInput" Margin="0,130,10,0" Grid.Column="1" Grid.ColumnSpan="3"
                          TextChanged="TextBox_TextChanged"/>
diff --git a/Elwig/Windows/MemberAdminWindow.xaml.cs b/Elwig/Windows/MemberAdminWindow.xaml.cs
index 4a4858e..b4986d3 100644
--- a/Elwig/Windows/MemberAdminWindow.xaml.cs
+++ b/Elwig/Windows/MemberAdminWindow.xaml.cs
@@ -347,6 +347,13 @@ namespace Elwig.Windows {
             FamilyNameInput.Text = m.FamilyName;
             SuffixInput.Text = m.Suffix;
             BirthdayInput.Text = (m.Birthday != null) ? string.Join(".", m.Birthday.Split("-").Reverse()) : null;
+            if (m.Birthday?.Length == 10) {
+                Age.Text = Utils.GetAge(DateOnly.ParseExact(m.Birthday, "yyyy-MM-dd")).ToString();
+            } else if (m.Birthday != null) {
+                Age.Text = "ca. " + (DateTime.Now.Year - int.Parse(m.Birthday[^4..])).ToString();
+            } else {
+                Age.Text = "-";
+            }
             AddressInput.Text = m.Address;
             AT_PlzDest? p = m.PostalDest.AtPlz;
             if (p != null) {
@@ -412,6 +419,7 @@ namespace Elwig.Windows {
         new protected void ClearInputs() {
             Menu_Member_SendEmail.IsEnabled = false;
             AreaCommitment.Text = "- m²";
+            Age.Text = "-";
             base.ClearInputs();
         }