diff --git a/AK/StringUtils.cpp b/AK/StringUtils.cpp
index 9ad58da156..78d49a48e2 100644
--- a/AK/StringUtils.cpp
+++ b/AK/StringUtils.cpp
@@ -116,7 +116,8 @@ Optional<T> convert_to_int(const StringView& str, TrimWhitespace trim_whitespace
 template Optional<i8> convert_to_int(const StringView& str, TrimWhitespace);
 template Optional<i16> convert_to_int(const StringView& str, TrimWhitespace);
 template Optional<i32> convert_to_int(const StringView& str, TrimWhitespace);
-template Optional<i64> convert_to_int(const StringView& str, TrimWhitespace);
+template Optional<long> convert_to_int(const StringView& str, TrimWhitespace);
+template Optional<long long> convert_to_int(const StringView& str, TrimWhitespace);
 
 template<typename T>
 Optional<T> convert_to_uint(const StringView& str, TrimWhitespace trim_whitespace)
@@ -146,7 +147,8 @@ Optional<T> convert_to_uint(const StringView& str, TrimWhitespace trim_whitespac
 template Optional<u8> convert_to_uint(const StringView& str, TrimWhitespace);
 template Optional<u16> convert_to_uint(const StringView& str, TrimWhitespace);
 template Optional<u32> convert_to_uint(const StringView& str, TrimWhitespace);
-template Optional<u64> convert_to_uint(const StringView& str, TrimWhitespace);
+template Optional<unsigned long> convert_to_uint(const StringView& str, TrimWhitespace);
+template Optional<unsigned long long> convert_to_uint(const StringView& str, TrimWhitespace);
 template Optional<long> convert_to_uint(const StringView& str, TrimWhitespace);
 template Optional<long long> convert_to_uint(const StringView& str, TrimWhitespace);
 
diff --git a/AK/StringView.cpp b/AK/StringView.cpp
index 83f90e2d3c..205f282d70 100644
--- a/AK/StringView.cpp
+++ b/AK/StringView.cpp
@@ -215,7 +215,8 @@ Optional<T> StringView::to_int() const
 template Optional<i8> StringView::to_int() const;
 template Optional<i16> StringView::to_int() const;
 template Optional<i32> StringView::to_int() const;
-template Optional<i64> StringView::to_int() const;
+template Optional<long> StringView::to_int() const;
+template Optional<long long> StringView::to_int() const;
 
 template<typename T>
 Optional<T> StringView::to_uint() const
@@ -226,7 +227,8 @@ Optional<T> StringView::to_uint() const
 template Optional<u8> StringView::to_uint() const;
 template Optional<u16> StringView::to_uint() const;
 template Optional<u32> StringView::to_uint() const;
-template Optional<u64> StringView::to_uint() const;
+template Optional<unsigned long> StringView::to_uint() const;
+template Optional<unsigned long long> StringView::to_uint() const;
 template Optional<long> StringView::to_uint() const;
 template Optional<long long> StringView::to_uint() const;