diff --git a/numberConverter.py b/numberConverter.py
new file mode 100644
index 0000000..362339f
--- /dev/null
+++ b/numberConverter.py
@@ -0,0 +1,78 @@
+# convert numbers into different number systems
+# iterative version
+import sys
+
+
+def user_input():
+    number = int(input('decimal number to convert: '))
+    return number
+
+def decimal_to_binary(number):
+    # decimal to binary
+    decimal_number = ''
+    # set div to a number to make the while loop work
+    div = 1 
+    while (div != 0):
+        div = number // 2
+        reminder = number % 2
+        number = div
+        #print(reminder)
+        decimal_number += str(reminder)
+    return print('binary: ', decimal_number[::-1]) 
+
+def decimal_to_octal(number):
+    octal_number = ''
+    div = 1
+    while (div != 0):
+        div = number // 8
+        reminder = number % 8
+        number = div
+        octal_number += str(reminder)
+    return print('octal: ', octal_number[::-1])
+
+def decimal_to_duodecimal(number):
+    duodecimal_number = ''
+    div = 1
+    while (div != 0):
+        div = number // 12
+        reminder = number % 12
+        if (reminder > 9):
+           reminder = switcher(reminder)
+        number = div
+        duodecimal_number += str(reminder)
+    return print('duodecimal: ', duodecimal_number[::-1]) 
+  
+def decimal_to_hex(number):
+    hex_number = ''
+    div = 1
+    while (div != 0):
+        div = number // 16
+        reminder = number % 16
+        if (reminder > 9):
+           reminder = switcher(reminder)
+        number = div
+        hex_number += str(reminder)
+    return print('hexadezimal: ', hex_number[::-1])
+
+# switcher to select the correct char for hex number lager then 9
+def switcher(n):
+    switcher = {
+            10: 'A',
+            11: 'B',
+            12: 'C',
+            13: 'D',
+            14: 'E',
+            15: 'F'
+            }
+    return switcher.get(n)
+
+def main():
+    number = user_input()
+    decimal_to_binary(number)
+    decimal_to_octal(number)
+    decimal_to_duodecimal(number)
+    decimal_to_hex(number)
+
+if __name__ == "__main__":
+    main()
+