diff --git a/README.md b/README.md
index 86b71e3..115bf0f 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,10 @@
-# template
+# 6to4_converter
 
 ## Description
+Simple script to convert IPv4 addresses to 6to4 addresses. See RFC 3056 for details.
 
 ## How to install
+- Clone the repository.
 
 ## How to use
+- Run `python3 app/main.py --help` for information on how to use this script.
diff --git a/requirements.txt b/app/__init__.py
similarity index 100%
rename from requirements.txt
rename to app/__init__.py
diff --git a/app/main.py b/app/main.py
index a6053f8..3bcbf51 100644
--- a/app/main.py
+++ b/app/main.py
@@ -1,8 +1,54 @@
-#!/usr/local/bin/python3
+#!/usr/bin/env python3
 
-def main():
-    # Commands here
-    
+"""Get 6to4 address from IPv4 address."""
 
-if __name__ == "__main__":
-    main()
+import argparse
+
+
+def parse_args():  # pragma: no cover
+    parser = argparse.ArgumentParser(description='Get 6to4 address from IPv4 address.')
+    parser.add_argument('-a', '--address', dest='address', action='store', help='IPv4 address', required=True)
+    args = parser.parse_args()
+    return args
+
+
+def ipv4_to_ipv6(ipv4):
+    ipv4Hex = ''
+    ipv6Hextet1 = '2002'
+    ipv6Hextet2 = ''
+    ipv6Hextet3 = ''
+
+    # Split input to octets
+    ipv4 = ipv4.split('.',4)
+
+    # Convert IPv4 address to hex string
+    for octet in ipv4:
+        if len(hex(int(octet))[2:])>1:
+            ipv4Hex += hex(int(octet))[2:]
+        else:
+            ipv4Hex += '0'
+            ipv4Hex += hex(int(octet))[2:]
+
+    # Split into hextets
+    for i in range(4):
+        ipv6Hextet2 += (ipv4Hex[i])
+    for i in range(4,8):
+        ipv6Hextet3 += (ipv4Hex[i])
+
+    # Convert to dec and back to remove leading zeros
+    ipv6Hextet2 = hex(int(ipv6Hextet2,16))[2:]
+    ipv6Hextet3 = hex(int(ipv6Hextet3,16))[2:]
+
+    # Form 6to4 address
+    output_6to4 = f"{ipv6Hextet1}:{ipv6Hextet2}:{ipv6Hextet3}::/128"
+    return output_6to4
+
+
+def main():  # pragma: no cover
+    ipv4 = parse_args().address
+    output = ipv4_to_ipv6(ipv4)
+    print(output)
+
+
+if __name__ == '__main__':
+    main()  # pragma: no cover
diff --git a/tests/__init__.py b/tests/__init__.py
new file mode 100644
index 0000000..e69de29
diff --git a/tests/test_main.py b/tests/test_main.py
index e69de29..8f4f589 100644
--- a/tests/test_main.py
+++ b/tests/test_main.py
@@ -0,0 +1,9 @@
+#!/usr/bin/env python3
+
+"""Test cases for main.py."""
+
+from app.main import ipv4_to_ipv6
+
+def test_ipv4_to_ipv6():
+    result = ipv4_to_ipv6('192.168.0.1')
+    assert result == "2002:c0a8:1::/128"