diff --git a/src/epub_converter/css_processor.py b/src/epub_converter/css_processor.py
index 4a1d9d5..5335ecd 100644
--- a/src/epub_converter/css_processor.py
+++ b/src/epub_converter/css_processor.py
@@ -57,7 +57,7 @@ class CSSPreprocessor:
     def convert_tag_style_values(size_value: str, is_indent: bool = False) -> str:
         """
         Function
-        - converts values of tags from em/%/pt to px
+        - converts values of tags from em/%/pt/in to px
         - find closest font-size px
         Parameters
         ----------
@@ -71,7 +71,7 @@ class CSSPreprocessor:
             converted value size
         """
         size_regexp = re.compile(
-            r"(^-*(\d*\.*\d+)%$)|(^-*(\d*\.*\d+)em$)|(^-*(\d*\.*\d+)pt$)")
+            r"(^-*(\d*\.*\d+)%$)|(^-*(\d*\.*\d+)em$)|(^-*(\d*\.*\d+)pt$)|(^-*(\d*\.*\d+)in$)")
         has_style_attrs = re.search(size_regexp, size_value)
         if has_style_attrs:
             if has_style_attrs.group(1):
@@ -85,6 +85,9 @@ class CSSPreprocessor:
             elif has_style_attrs.group(5):
                 size_value = float(size_value.replace("pt", "")) * 4/3
                 return str(size_value)+'px'
+            elif has_style_attrs.group(7):
+                size_value = float(size_value.replace("in", "")) * 96
+                return str(size_value)+'px'
             else:
                 return ""
         return size_value