diff --git a/translator/common/__init.py__ b/translator/common/__init.py__
new file mode 100644
index 00000000..e69de29b
diff --git a/translator/common/__init__.py b/translator/common/__init__.py
new file mode 100644
index 00000000..e69de29b
diff --git a/translator/common/utils.py b/translator/common/utils.py
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--- /dev/null
+++ b/translator/common/utils.py
@@ -0,0 +1,70 @@
+#    Licensed under the Apache License, Version 2.0 (the "License"); you may
+#    not use this file except in compliance with the License. You may obtain
+#    a copy of the License at
+#
+#         http://www.apache.org/licenses/LICENSE-2.0
+#
+#    Unless required by applicable law or agreed to in writing, software
+#    distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+#    WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+#    License for the specific language governing permissions and limitations
+#    under the License.
+
+
+import math
+import numbers
+import re
+from translator.toscalib.utils.gettextutils import _
+
+
+class MemoryUnit(object):
+
+    UNIT_SIZE_DEFAULT = 'B'
+    UNIT_SIZE_DICT = {'B': 1, 'KB': 1000, 'KIB': 1024, 'MB': 1000000,
+                      'MIB': 1048576, 'GB': 1000000000,
+                      'GIB': 1073741824, 'TB': 1000000000000,
+                      'TIB': 1099511627776}
+
+    @staticmethod
+    def convert_unit_size_to_num(size, unit=None):
+        """Convert given size to a number representing given unit.
+        If unit is None, convert to a number representing UNIT_SIZE_DEFAULT
+
+        :param size: unit size e.g. 1 TB
+        :param unit: unit to be converted to e.g GB
+        :return: converted number e.g. 1000 for 1 TB size and unit GB
+        """
+
+        if unit:
+            MemoryUnit.validate_unit(unit)
+        else:
+            unit = MemoryUnit.UNIT_SIZE_DEFAULT
+
+        regex = re.compile('(\d*)\s*(\w*)')
+        result = regex.match(str(size)).groups()
+        if result[1]:
+            MemoryUnit.validate_unit(result[1])
+            converted = int(str_to_num(result[0])
+                            * MemoryUnit.UNIT_SIZE_DICT[result[1].upper()]
+                            * math.pow(MemoryUnit.UNIT_SIZE_DICT
+                                       [unit.upper()], -1))
+        else:
+            converted = (str_to_num(result[0]))
+        return converted
+
+    @staticmethod
+    def validate_unit(unit):
+        if unit.upper() not in MemoryUnit.UNIT_SIZE_DICT.keys():
+            msg = _('Provided unit "{0}" is not valid. The valid units are '
+                    '{1}').format(unit, MemoryUnit.UNIT_SIZE_DICT.keys())
+            raise ValueError(msg)
+
+
+def str_to_num(value):
+    '''Convert a string representation of a number into a numeric type.'''
+    if isinstance(value, numbers.Number):
+        return value
+    try:
+        return int(value)
+    except ValueError:
+        return float(value)