diff --git a/conversion/stringbuilder.h b/conversion/stringbuilder.h
index e8ab834..93b3978 100644
--- a/conversion/stringbuilder.h
+++ b/conversion/stringbuilder.h
@@ -12,18 +12,18 @@ namespace ConversionUtilities {
 /// \cond
 namespace Helper {
 
-template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> std::size_t computeTupleElementSize(const StringType *str)
+template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> inline std::size_t computeTupleElementSize(const StringType *str)
 {
     return str->size();
 }
 
-template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> std::size_t computeTupleElementSize(const StringType &str)
+template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> inline std::size_t computeTupleElementSize(const StringType &str)
 {
     return str.size();
 }
 
 template <class StringType, class CharType, Traits::EnableIf<std::is_same<typename StringType::value_type, CharType>> * = nullptr>
-std::size_t computeTupleElementSize(const CharType *str)
+constexpr std::size_t computeTupleElementSize(const CharType *str)
 {
     return std::char_traits<CharType>::length(str);
 }
@@ -37,7 +37,7 @@ constexpr std::size_t computeTupleElementSize(CharType)
 template <class StringType, typename IntegralType,
     Traits::EnableIf<Traits::Not<std::is_same<typename StringType::value_type, IntegralType>>, std::is_integral<IntegralType>,
         std::is_unsigned<IntegralType>> * = nullptr>
-std::size_t computeTupleElementSize(IntegralType number, typename StringType::value_type base = 10)
+constexpr std::size_t computeTupleElementSize(IntegralType number, typename StringType::value_type base = 10)
 {
     std::size_t size = 0;
     for (auto n = number; n; n /= base, ++size)
@@ -48,7 +48,7 @@ std::size_t computeTupleElementSize(IntegralType number, typename StringType::va
 template <class StringType, typename IntegralType,
     Traits::EnableIf<Traits::Not<std::is_same<typename StringType::value_type, IntegralType>>, std::is_integral<IntegralType>,
         std::is_signed<IntegralType>> * = nullptr>
-std::size_t computeTupleElementSize(IntegralType number, typename StringType::value_type base = 10)
+constexpr std::size_t computeTupleElementSize(IntegralType number, typename StringType::value_type base = 10)
 {
     std::size_t size = number < 0 ? 1 : 0;
     for (auto n = number; n; n /= base, ++size)
@@ -56,24 +56,24 @@ std::size_t computeTupleElementSize(IntegralType number, typename StringType::va
     return size;
 }
 
-template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> void append(StringType &target, const StringType *str)
+template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> inline void append(StringType &target, const StringType *str)
 {
     target.append(*str);
 }
 
-template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> void append(StringType &target, const StringType &str)
+template <class StringType, Traits::EnableIf<std::is_class<StringType>> * = nullptr> inline void append(StringType &target, const StringType &str)
 {
     target.append(str);
 }
 
 template <class StringType, class CharType, Traits::EnableIf<std::is_same<typename StringType::value_type, CharType>> * = nullptr>
-void append(StringType &target, const CharType *str)
+inline void append(StringType &target, const CharType *str)
 {
     target.append(str);
 }
 
 template <class StringType, class CharType, Traits::EnableIf<std::is_same<typename StringType::value_type, CharType>> * = nullptr>
-void append(StringType &target, CharType c)
+inline void append(StringType &target, CharType c)
 {
     target += c;
 }
@@ -81,7 +81,7 @@ void append(StringType &target, CharType c)
 template <class StringType, typename IntegralType,
     Traits::EnableIf<Traits::Not<std::is_same<typename StringType::value_type, IntegralType>>, std::is_integral<IntegralType>,
         std::is_unsigned<IntegralType>> * = nullptr>
-void append(StringType &target, IntegralType number, typename StringType::value_type base = 10)
+inline void append(StringType &target, IntegralType number, typename StringType::value_type base = 10)
 {
     const auto start = target.begin() + target.size();
     do {
@@ -93,7 +93,7 @@ void append(StringType &target, IntegralType number, typename StringType::value_
 template <class StringType, typename IntegralType,
     Traits::EnableIf<Traits::Not<std::is_same<typename StringType::value_type, IntegralType>>, std::is_integral<IntegralType>,
         std::is_signed<IntegralType>> * = nullptr>
-void append(StringType &target, IntegralType number, typename StringType::value_type base = 10)
+inline void append(StringType &target, IntegralType number, typename StringType::value_type base = 10)
 {
     if (number < 0) {
         target += '-';
@@ -107,12 +107,12 @@ void append(StringType &target, IntegralType number, typename StringType::value_
 }
 
 template <class StringType, class Tuple, std::size_t N> struct TupleToString {
-    static std::size_t precomputeSize(const Tuple &tuple)
+    static inline std::size_t precomputeSize(const Tuple &tuple)
     {
         return TupleToString<StringType, Tuple, N - 1>::precomputeSize(tuple) + computeTupleElementSize<StringType>(std::get<N - 1>(tuple));
     }
 
-    static void append(const Tuple &tuple, StringType &str)
+    static inline void append(const Tuple &tuple, StringType &str)
     {
         TupleToString<StringType, Tuple, N - 1>::append(tuple, str);
         Helper::append(str, std::get<N - 1>(tuple));
@@ -120,12 +120,12 @@ template <class StringType, class Tuple, std::size_t N> struct TupleToString {
 };
 
 template <class StringType, class Tuple> struct TupleToString<StringType, Tuple, 1> {
-    static std::size_t precomputeSize(const Tuple &tuple)
+    static inline std::size_t precomputeSize(const Tuple &tuple)
     {
         return computeTupleElementSize<StringType>(std::get<0>(tuple));
     }
 
-    static void append(const Tuple &tuple, StringType &str)
+    static inline void append(const Tuple &tuple, StringType &str)
     {
         Helper::append(str, std::get<0>(tuple));
     }
@@ -136,7 +136,7 @@ template <class StringType, class Tuple> struct TupleToString<StringType, Tuple,
 /*!
  * \brief Concatenates all strings hold by the specified \a tuple.
  */
-template <class StringType = std::string, class... Args> StringType tupleToString(const std::tuple<Args...> &tuple)
+template <class StringType = std::string, class... Args> inline StringType tupleToString(const std::tuple<Args...> &tuple)
 {
     StringType res;
     res.reserve(Helper::TupleToString<StringType, decltype(tuple), sizeof...(Args)>::precomputeSize(tuple));
@@ -144,7 +144,7 @@ template <class StringType = std::string, class... Args> StringType tupleToStrin
     return res;
 }
 
-template <class StringType = std::string, class... Args> constexpr StringType argsToString(Args &&... args)
+template <class StringType = std::string, class... Args> inline StringType argsToString(Args &&... args)
 {
     return tupleToString(std::make_tuple(args...));
 }