diff --git a/flask_app.py b/app.py
similarity index 60%
rename from flask_app.py
rename to app.py
index 8897fa2..157e0a8 100644
--- a/flask_app.py
+++ b/app.py
@@ -2,6 +2,8 @@
 
 from helper import perform_calculation, convert_to_float
 
+from circle import Circle
+
 app = Flask(__name__)  # create the instance of the flask class
 
 
@@ -38,3 +40,24 @@ def calculate():
             return render_template('calculator.html', printed_result="You cannot divide by zero")
 
     return render_template('calculator.html')
+
+
+@app.route('/calculate-circle', methods=['GET', 'POST'])
+def calculate_circle():
+    if request.method == 'POST':
+        radius = request.form['radius']
+        try:
+            radius = float(radius)
+        except:
+            return render_template('circle.html', radius = '', area='', perimeter='',
+                                   msg = f'The radius must be a number, not {type(radius)}.')
+        if radius <= 0:
+            return render_template('circle.html', radius = '', area='', perimeter='',
+                                   msg = f'The radius of the circle must be greater than zero. {radius} is less than zero.')
+        circle = Circle(radius)
+        return render_template('circle.html',
+                               msg = '',
+                               radius = radius,
+                               area = format(circle.area(), '.2f'),
+                               perimeter = format(circle.perimeter(), '.2f'))
+    return render_template('circle.html', radius = '', msg = '', area='', perimeter='')
\ No newline at end of file
diff --git a/circle.py b/circle.py
new file mode 100644
index 0000000..a509de3
--- /dev/null
+++ b/circle.py
@@ -0,0 +1,9 @@
+from math import pi
+
+class Circle:
+    def __init__(self, radius):
+        self.radius = radius
+    def perimeter(self):
+        return pi * 2 * self.radius
+    def area(self):
+        return pi * self.radius**2
\ No newline at end of file
diff --git a/static/main.css b/static/main.css
index dfe5192..13037df 100644
--- a/static/main.css
+++ b/static/main.css
@@ -97,3 +97,7 @@ button {
 button:hover {
     background-color: #23272b; /* Slightly darker color on hover */
 }
+
+.center {
+    text-align: center;
+}
\ No newline at end of file
diff --git a/templates/circle.html b/templates/circle.html
new file mode 100644
index 0000000..3144bb8
--- /dev/null
+++ b/templates/circle.html
@@ -0,0 +1,27 @@
+{% extends 'layout.html' %}
+{% block content %}
+	<h1>Circle Calculator</h1>
+    <form method="post">
+        <input type="text" name="radius" placeholder="Radius of the circle" required="required" />
+        <button type="submit">Calculate</button>
+    </form>
+
+   <br>
+
+   <div class='center'>
+    {{ msg }}
+   </div>
+   <div class='center'>
+    Radius: {{ radius }}
+   </div>
+   <br>
+   <div class='center'>
+    Area: {{ area }}
+   </div>
+   <br>
+   <div class='center'>
+    Perimeter: {{ perimeter }}
+   </div>
+   
+
+{% endblock %}
\ No newline at end of file
diff --git a/templates/layout.html b/templates/layout.html
index 8de2e62..ede7ca4 100644
--- a/templates/layout.html
+++ b/templates/layout.html
@@ -12,6 +12,7 @@ <h1 class="logo"><a href="{{ url_for('home') }}">Home</a></h1>
         <strong><nav>
           <ul class="menu">
             <li><a href="{{ url_for('calculate') }}">General Calculator</a></li>
+            <li><a href="{{ url_for('calculate_circle')}}">Circle Calculator</a></li>
           </ul>
         </nav></strong>
       </div>
diff --git a/test_circle.py b/test_circle.py
new file mode 100644
index 0000000..ce56624
--- /dev/null
+++ b/test_circle.py
@@ -0,0 +1,25 @@
+from circle import Circle
+from math import pi
+import random
+
+'''
+These tests are circular, but we're testing a toy example.
+I could have also hardcoded some precalculated perimeters and areas and tested it that way.
+I am not testing invalid inputs (e.g. radius = "five") here because I handle that via input validation in Flask.
+I would normally test the Flask app itself, but that is out of scope for this problem set.
+
+I run these tests via pytest test_circle.py
+'''
+
+
+
+def test_circle_perimeter():
+    radius = random.random() * 100
+    circle = Circle(radius)
+    assert circle.perimeter() == pi * 2 * radius
+
+
+def test_circle_area():
+    radius = random.random() * 100
+    circle = Circle(radius)
+    assert circle.area() == pi * radius**2
\ No newline at end of file