diff --git a/ChangeLog b/ChangeLog
index 3ef8115a..f5c3eb3d 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,6 @@
 2018-10-26  Markus Gans  <guru.mail@muenster.de>
 	* Building Fix for a negative value check (gcc < 4.8)
+	* Adding the capacity() method to the FString class
 
 2018-10-21  Markus Gans  <guru.mail@muenster.de>
 	* Moving static attributes from FApplication to FWidget
diff --git a/src/fstring.cpp b/src/fstring.cpp
index e0118090..b9c8cbea 100644
--- a/src/fstring.cpp
+++ b/src/fstring.cpp
@@ -1474,7 +1474,7 @@ inline void FString::_assign (const wchar_t s[])
 
   uInt new_length = uInt(std::wcslen(s));
 
-  if ( ! string || new_length > bufsize - 1 )
+  if ( ! string || new_length > capacity() )
   {
     if ( string )
       delete[](string);
@@ -1493,8 +1493,8 @@ inline void FString::_assign (const wchar_t s[])
   }
 
   std::wcsncpy (string, s, bufsize);
-  string[bufsize - 1] = L'\0';
   length = new_length;
+  string[capacity()] = L'\0';
 }
 
 //----------------------------------------------------------------------
@@ -1520,7 +1520,7 @@ inline void FString::_insert (std::size_t len, const wchar_t s[])
   }
 
   std::wcsncpy (string, s, bufsize);
-  string[bufsize - 1] = L'\0';
+  string[capacity()] = L'\0';
 }
 
 //----------------------------------------------------------------------
@@ -1539,7 +1539,7 @@ inline void FString::_insert ( std::size_t pos
   {
     std::size_t x;
 
-    if ( (length + len + 1) <= bufsize )
+    if ( length + len <= capacity() )
     {
       // output string <= bufsize
       for (x = length; x + 1 > pos; x--)  // shifting right side + '\0'
@@ -1587,7 +1587,7 @@ inline void FString::_insert ( std::size_t pos
 //----------------------------------------------------------------------
 inline void FString::_remove (std::size_t pos, std::size_t len)
 {
-  if ( (bufsize - length - 1 + len) <= FWDBUFFER )
+  if ( capacity() - length + len <= FWDBUFFER )
   {
     // shifting left side to pos
     for (std::size_t i = pos; i + len < length + 1; i++)
diff --git a/src/include/final/fstring.h b/src/include/final/fstring.h
index f8aaac09..8d3d9286 100644
--- a/src/include/final/fstring.h
+++ b/src/include/final/fstring.h
@@ -187,6 +187,7 @@ class FString
     // Methods
     std::size_t getLength() const;
     std::size_t getUTF8length() const;
+    std::size_t capacity() const;
 
     iterator begin() const;
     iterator end()   const;
@@ -368,6 +369,10 @@ inline bool FString::isEmpty() const
 inline std::size_t FString::getLength() const
 { return length; }
 
+//----------------------------------------------------------------------
+inline std::size_t FString::capacity() const
+{ return ( length > 0 ) ? bufsize - 1 : 0; }
+
 //----------------------------------------------------------------------
 inline FString::iterator FString::begin() const
 { return string; }
diff --git a/test/fstring-test.cpp b/test/fstring-test.cpp
index 451d61e9..11e46b01 100644
--- a/test/fstring-test.cpp
+++ b/test/fstring-test.cpp
@@ -162,6 +162,7 @@ void FStringTest::noArgumentTest()
   CPPUNIT_ASSERT ( empty.isNull() );
   CPPUNIT_ASSERT ( empty.isEmpty() );
   CPPUNIT_ASSERT ( empty.getLength() == 0 );
+  CPPUNIT_ASSERT ( empty.capacity() == 0 );
   CPPUNIT_ASSERT ( empty.getUTF8length() == 0 );
   CPPUNIT_ASSERT ( empty.wc_str() == 0 );
   CPPUNIT_ASSERT ( empty.c_str() == 0 );
@@ -177,6 +178,7 @@ void FStringTest::noArgumentTest()
   CPPUNIT_ASSERT ( wcstr == 0 );
   std::string str = empty.toString();
   CPPUNIT_ASSERT ( str.length() == 0 );
+  CPPUNIT_ASSERT ( str.capacity() == 15 );
   CPPUNIT_ASSERT ( str.size() == 0 );
   CPPUNIT_ASSERT ( str.empty() );
   const finalcut::FString fstr = str;
@@ -217,6 +219,7 @@ void FStringTest::initLengthTest()
 {
   const finalcut::FString s1(0);
   CPPUNIT_ASSERT ( s1.getLength() == 0 );
+  CPPUNIT_ASSERT ( s1.capacity() == 0 );
   CPPUNIT_ASSERT ( s1.isNull() );
   CPPUNIT_ASSERT ( s1.isEmpty() );
 
@@ -224,26 +227,31 @@ void FStringTest::initLengthTest()
   const std::size_t x2 = 10;
   const finalcut::FString s2(x1);
   CPPUNIT_ASSERT ( s2.getLength() == 10 );
+  CPPUNIT_ASSERT ( s2.capacity() == 25 );
   CPPUNIT_ASSERT ( ! s2.isNull() );
   CPPUNIT_ASSERT ( s2.isEmpty() );
 
   const finalcut::FString s3(x2);
   CPPUNIT_ASSERT ( s3.getLength() == 10 );
+  CPPUNIT_ASSERT ( s3.capacity() == 25 );
   CPPUNIT_ASSERT ( ! s3.isNull() );
   CPPUNIT_ASSERT ( s3.isEmpty() );
 
   const finalcut::FString s4(0, L'-');
   CPPUNIT_ASSERT ( s4.getLength() == 0 );
+  CPPUNIT_ASSERT ( s4.capacity() == 0 );
   CPPUNIT_ASSERT ( s4.isNull() );
   CPPUNIT_ASSERT ( s4.isEmpty() );
 
   const finalcut::FString s5(0, '-');
   CPPUNIT_ASSERT ( s5.getLength() == 0 );
+  CPPUNIT_ASSERT ( s5.capacity() == 0 );
   CPPUNIT_ASSERT ( s5.isNull() );
   CPPUNIT_ASSERT ( s5.isEmpty() );
 
   const finalcut::FString s6(0, char(0));
   CPPUNIT_ASSERT ( s6.getLength() == 0 );
+  CPPUNIT_ASSERT ( s6.capacity() == 0 );
   CPPUNIT_ASSERT ( s6.isNull() );
   CPPUNIT_ASSERT ( s6.isEmpty() );
 
@@ -254,21 +262,25 @@ void FStringTest::initLengthTest()
 
   const finalcut::FString s8(x2, '-');
   CPPUNIT_ASSERT ( s8.getLength() == 10 );
+  CPPUNIT_ASSERT ( s8.capacity() == 25 );
   CPPUNIT_ASSERT ( ! s8.isNull() );
   CPPUNIT_ASSERT ( ! s8.isEmpty() );
 
   const finalcut::FString s9(x1, L'-');
   CPPUNIT_ASSERT ( s9.getLength() == 10 );
+  CPPUNIT_ASSERT ( s9.capacity() == 25 );
   CPPUNIT_ASSERT ( ! s9.isNull() );
   CPPUNIT_ASSERT ( ! s9.isEmpty() );
 
   const finalcut::FString s10(x2, L'-');
   CPPUNIT_ASSERT ( s10.getLength() == 10 );
+  CPPUNIT_ASSERT ( s10.capacity() == 25 );
   CPPUNIT_ASSERT ( ! s10.isNull() );
   CPPUNIT_ASSERT ( ! s10.isEmpty() );
 
   const finalcut::FString s11(x2, wchar_t(0));
   CPPUNIT_ASSERT ( s11.getLength() == 10 );
+  CPPUNIT_ASSERT ( s11.capacity() == 25 );
   CPPUNIT_ASSERT ( ! s11.isNull() );
   CPPUNIT_ASSERT ( s11.isEmpty() );
 }
@@ -280,6 +292,7 @@ void FStringTest::copyConstructorTest()
   const finalcut::FString s2(s1);
   CPPUNIT_ASSERT ( s2 == L"abc" );
   CPPUNIT_ASSERT ( s2.getLength() == 3 );
+  CPPUNIT_ASSERT ( s2.capacity() == 18 );
 }
 
 //----------------------------------------------------------------------
@@ -326,42 +339,49 @@ void FStringTest::assignmentTest()
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"abc" );
   CPPUNIT_ASSERT ( s1.getLength() == 3 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   const std::wstring s3(L"def");
   s1 = s3;
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"def" );
   CPPUNIT_ASSERT ( s1.getLength() == 3 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   const std::string s4("ghi");
   s1 = s4;
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"ghi" );
   CPPUNIT_ASSERT ( s1.getLength() == 3 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   const wchar_t s5[] = L"abc";
   s1 = s5;
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"abc" );
   CPPUNIT_ASSERT ( s1.getLength() == 3 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   const char s6[] = "def";
   s1 = s6;
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"def" );
   CPPUNIT_ASSERT ( s1.getLength() == 3 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   const wchar_t s7 = L'#';
   s1 = s7;
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"#" );
   CPPUNIT_ASSERT ( s1.getLength() == 1 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   const char s8 = '%';
   s1 = s8;
   CPPUNIT_ASSERT ( s1 );
   CPPUNIT_ASSERT ( s1 == L"%" );
   CPPUNIT_ASSERT ( s1.getLength() == 1 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
 
   s1.setString("A character string");
   CPPUNIT_ASSERT ( s1 );
@@ -537,6 +557,7 @@ void FStringTest::equalTest()
   CPPUNIT_ASSERT ( one_char == ch );
   CPPUNIT_ASSERT ( ch == one_char.c_str()[0] );
   CPPUNIT_ASSERT ( one_char.getLength() == 1 );
+  CPPUNIT_ASSERT ( one_char.capacity() == 16 );
 
   const wchar_t wch = L'a';
   CPPUNIT_ASSERT ( one_char == wch );
@@ -550,6 +571,7 @@ void FStringTest::equalTest()
   CPPUNIT_ASSERT ( str == cstr );
   CPPUNIT_ASSERT ( str.getLength() == 3 );
   CPPUNIT_ASSERT ( str.getUTF8length() == 3 );
+  CPPUNIT_ASSERT ( str.capacity() == 18 );
   CPPUNIT_ASSERT ( strncmp(cstr, str.c_str(), 3) == 0 );
 
   const wchar_t wcstr[] = L"abc";
@@ -570,6 +592,7 @@ void FStringTest::equalTest()
 
   CPPUNIT_ASSERT ( s->c_str()[0] == 'c');
   CPPUNIT_ASSERT ( s->getLength() == 1 );
+  CPPUNIT_ASSERT ( s->capacity() == 16 );
 }
 
 //----------------------------------------------------------------------
@@ -580,6 +603,7 @@ void FStringTest::notEqualTest()
   CPPUNIT_ASSERT ( one_char != ch );
   CPPUNIT_ASSERT ( ch != one_char.c_str()[0] );
   CPPUNIT_ASSERT ( one_char.getLength() == 1 );
+  CPPUNIT_ASSERT ( one_char.capacity() == 16 );
 
   const wchar_t wch = L'_';
   CPPUNIT_ASSERT ( one_char != wch );
@@ -597,6 +621,8 @@ void FStringTest::notEqualTest()
   CPPUNIT_ASSERT ( strlen(s2.c_str()) == 6 );
   CPPUNIT_ASSERT ( s1.getUTF8length() == 3 );
   CPPUNIT_ASSERT ( s2.getUTF8length() == 3 );
+  CPPUNIT_ASSERT ( s1.capacity() == 18 );
+  CPPUNIT_ASSERT ( s2.capacity() == 18 );
   CPPUNIT_ASSERT ( strncmp(cstr, s1.c_str(), 3) != 0 );
 
   const wchar_t wcstr[] = L"abc";
@@ -1236,21 +1262,25 @@ void FStringTest::trimTest()
   CPPUNIT_ASSERT ( trim_str2.rtrim().isEmpty() );
   CPPUNIT_ASSERT ( ! trim_str2.rtrim().isNull() );
   CPPUNIT_ASSERT ( trim_str2.rtrim().getLength() == 0 );
-
+  CPPUNIT_ASSERT ( trim_str2.rtrim().capacity() == 0 );
   CPPUNIT_ASSERT ( trim_str2.ltrim().isEmpty() );
   CPPUNIT_ASSERT ( ! trim_str2.ltrim().isNull() );
   CPPUNIT_ASSERT ( trim_str2.ltrim().getLength() == 0 );
+  CPPUNIT_ASSERT ( trim_str2.ltrim().capacity() == 0 );
 
   const finalcut::FString trim_str3;
   CPPUNIT_ASSERT ( trim_str3.ltrim().isEmpty() );
   CPPUNIT_ASSERT ( trim_str3.ltrim().isEmpty() );
   CPPUNIT_ASSERT ( trim_str3.ltrim().getLength() == 0 );
+  CPPUNIT_ASSERT ( trim_str3.ltrim().capacity() == 0 );
   CPPUNIT_ASSERT ( trim_str3.rtrim().isEmpty() );
   CPPUNIT_ASSERT ( trim_str3.rtrim().isEmpty() );
   CPPUNIT_ASSERT ( trim_str3.rtrim().getLength() == 0 );
+  CPPUNIT_ASSERT ( trim_str3.rtrim().capacity() == 0 );
   CPPUNIT_ASSERT ( trim_str3.trim().isEmpty() );
   CPPUNIT_ASSERT ( trim_str3.trim().isNull() );
   CPPUNIT_ASSERT ( trim_str3.trim().getLength() == 0 );
+  CPPUNIT_ASSERT ( trim_str3.trim().capacity() == 0 );
 }
 
 //----------------------------------------------------------------------