diff --git a/AK/String.cpp b/AK/String.cpp
index 4023451fa30..ba6b980f845 100644
--- a/AK/String.cpp
+++ b/AK/String.cpp
@@ -55,6 +55,11 @@ String String::from_utf8_without_validation(ReadonlyBytes bytes)
     return result;
 }
 
+String String::from_ascii_without_validation(ReadonlyBytes bytes)
+{
+    return from_utf8_without_validation(bytes);
+}
+
 ErrorOr<String> String::from_utf8(StringView view)
 {
     if (!Utf8View { view }.validate())
diff --git a/AK/String.h b/AK/String.h
index 5e2f481ccf6..9aef4f886a3 100644
--- a/AK/String.h
+++ b/AK/String.h
@@ -64,6 +64,7 @@ public:
     static ErrorOr<String> from_utf8(T&&) = delete;
 
     [[nodiscard]] static String from_utf8_without_validation(ReadonlyBytes);
+    [[nodiscard]] static String from_ascii_without_validation(ReadonlyBytes);
 
     static ErrorOr<String> from_string_builder(Badge<StringBuilder>, StringBuilder&);
     [[nodiscard]] static String from_string_builder_without_validation(Badge<StringBuilder>, StringBuilder&);
diff --git a/AK/StringNumber.h b/AK/StringNumber.h
index 54f5395fc1b..f12b29fd0c9 100644
--- a/AK/StringNumber.h
+++ b/AK/StringNumber.h
@@ -46,7 +46,7 @@ StringType create_string_from_number(T value)
     }
 
     size_t size = buffer + max_digits - ptr;
-    return StringType::from_utf8_without_validation(ReadonlyBytes { ptr, size });
+    return StringType::from_ascii_without_validation(ReadonlyBytes { ptr, size });
 }
 
 }
diff --git a/AK/Utf16String.cpp b/AK/Utf16String.cpp
index b98eb54c46a..c2985688b89 100644
--- a/AK/Utf16String.cpp
+++ b/AK/Utf16String.cpp
@@ -37,6 +37,21 @@ Utf16String Utf16String::from_utf8_with_replacement_character(StringView utf8_st
     return builder.to_utf16_string();
 }
 
+Utf16String Utf16String::from_ascii_without_validation(ReadonlyBytes ascii_string)
+{
+    if (ascii_string.size() <= Detail::MAX_SHORT_STRING_BYTE_COUNT) {
+        Utf16String string;
+        string.m_value.short_ascii_string = Detail::ShortString::create_with_byte_count(ascii_string.size());
+
+        auto result = ascii_string.copy_to(string.m_value.short_ascii_string.storage);
+        VERIFY(result == ascii_string.size());
+
+        return string;
+    }
+
+    return Utf16String { Detail::Utf16StringData::from_ascii(ascii_string) };
+}
+
 Utf16String Utf16String::from_utf8_without_validation(StringView utf8_string)
 {
     if (utf8_string.length() <= Detail::MAX_SHORT_STRING_BYTE_COUNT && utf8_string.is_ascii()) {
diff --git a/AK/Utf16String.h b/AK/Utf16String.h
index bc31932cede..7e1028333bd 100644
--- a/AK/Utf16String.h
+++ b/AK/Utf16String.h
@@ -64,6 +64,7 @@ public:
     }
 
     static Utf16String from_utf8_without_validation(StringView);
+    static Utf16String from_ascii_without_validation(ReadonlyBytes);
 
     static Utf16String from_utf16(Utf16View const& utf16_string);
 
diff --git a/AK/Utf16StringData.cpp b/AK/Utf16StringData.cpp
index 3f7bdddbc93..c51a111d622 100644
--- a/AK/Utf16StringData.cpp
+++ b/AK/Utf16StringData.cpp
@@ -56,6 +56,14 @@ NonnullRefPtr<Utf16StringData> Utf16StringData::create_from_code_point_iterable(
     return string;
 }
 
+NonnullRefPtr<Utf16StringData> Utf16StringData::from_ascii(ReadonlyBytes ascii_string)
+{
+    VERIFY_UTF16_LENGTH(ascii_string.size());
+    auto string = create_uninitialized(StorageType::ASCII, ascii_string.size());
+    TypedTransfer<char>::copy(string->m_ascii_data, reinterpret_cast<char const*>(ascii_string.data()), ascii_string.size());
+    return string;
+}
+
 NonnullRefPtr<Utf16StringData> Utf16StringData::from_utf8(StringView utf8_string, AllowASCIIStorage allow_ascii_storage)
 {
     RefPtr<Utf16StringData> string;
diff --git a/AK/Utf16StringData.h b/AK/Utf16StringData.h
index 350efa158a7..8d85ae5358b 100644
--- a/AK/Utf16StringData.h
+++ b/AK/Utf16StringData.h
@@ -31,6 +31,7 @@ public:
     };
 
     static NonnullRefPtr<Utf16StringData> from_utf8(StringView, AllowASCIIStorage);
+    static NonnullRefPtr<Utf16StringData> from_ascii(ReadonlyBytes);
     static NonnullRefPtr<Utf16StringData> from_utf16(Utf16View const&);
     static NonnullRefPtr<Utf16StringData> from_utf32(Utf32View const&);
     static NonnullRefPtr<Utf16StringData> from_string_builder(StringBuilder&);