diff --git a/src/3rdparty/squirrel/squirrel/sqlexer.cpp b/src/3rdparty/squirrel/squirrel/sqlexer.cpp
index 96e43f4af7..89eae0026e 100644
--- a/src/3rdparty/squirrel/squirrel/sqlexer.cpp
+++ b/src/3rdparty/squirrel/squirrel/sqlexer.cpp
@@ -11,7 +11,7 @@
 #include "sqcompiler.h"
 #include "sqlexer.h"
 
-#include "../../../string_func.h"
+#include "../../../core/utf8.hpp"
 
 #include "../../../safeguards.h"
 
@@ -28,8 +28,7 @@ SQLexer::~SQLexer()
 
 void SQLexer::APPEND_CHAR(char32_t c)
 {
-	char buf[4];
-	size_t chars = Utf8Encode(buf, c);
+	auto [buf, chars] = EncodeUtf8(c);
 	for (size_t i = 0; i < chars; i++) {
 		_longstr.push_back(buf[i]);
 	}
diff --git a/src/newgrf/newgrf_act0_globalvar.cpp b/src/newgrf/newgrf_act0_globalvar.cpp
index 3f765b79fd..d1e4f30ead 100644
--- a/src/newgrf/newgrf_act0_globalvar.cpp
+++ b/src/newgrf/newgrf_act0_globalvar.cpp
@@ -14,6 +14,7 @@
 #include "../language.h"
 #include "../rev.h"
 #include "../string_func.h"
+#include "../core/utf8.hpp"
 #include "../newgrf.h"
 #include "../newgrf_badge.h"
 #include "../newgrf_badge_type.h"
@@ -295,9 +296,8 @@ static ChangeInfoResult GlobalVarChangeInfo(uint first, uint last, int prop, Byt
 					 * safe as OpenTTD's strings gender/cases are usually in ASCII which
 					 * is just a subset of UTF8, or they need the bigger UTF8 characters
 					 * such as Cyrillic. Thus we will simply assume they're all UTF8. */
-					char32_t c;
-					size_t len = Utf8Decode(&c, name.data());
-					if (len <= name.size() && c == NFO_UTF8_IDENTIFIER) name = name.substr(len);
+					auto [len, c] = DecodeUtf8(name);
+					if (c == NFO_UTF8_IDENTIFIER) name.remove_prefix(len);
 
 					LanguageMap::Mapping map;
 					map.newgrf_id = newgrf_id;
diff --git a/src/textbuf.cpp b/src/textbuf.cpp
index 9b4573d0da..111be15df0 100644
--- a/src/textbuf.cpp
+++ b/src/textbuf.cpp
@@ -127,12 +127,10 @@ void Textbuf::DeleteAll()
  */
 bool Textbuf::InsertChar(char32_t key)
 {
-	uint16_t len = (uint16_t)Utf8CharLen(key);
+	auto [src, len] = EncodeUtf8(key);
 	if (this->buf.size() + len < this->max_bytes && this->chars + 1 <= this->max_chars) {
 		/* Make space in the string, then overwrite it with the Utf8 encoded character. */
-		auto pos = this->buf.begin() + this->caretpos;
-		pos = this->buf.insert(pos, len, '\0');
-		Utf8Encode(pos, key);
+		this->buf.insert(this->caretpos, src, len);
 		this->chars++;
 		this->caretpos += len;
 
diff --git a/src/video/sdl2_v.cpp b/src/video/sdl2_v.cpp
index 0863719a88..799f05c960 100644
--- a/src/video/sdl2_v.cpp
+++ b/src/video/sdl2_v.cpp
@@ -17,6 +17,7 @@
 #include "../core/math_func.hpp"
 #include "../core/mem_func.hpp"
 #include "../core/geometry_func.hpp"
+#include "../core/utf8.hpp"
 #include "../fileio_func.h"
 #include "../framerate_type.h"
 #include "../window_func.h"
@@ -497,9 +498,8 @@ bool VideoDriver_SDL_Base::PollEvent()
 			uint keycode = ConvertSdlKeycodeIntoMy(kc);
 
 			if (keycode == WKC_BACKQUOTE && FocusedWindowIsConsole()) {
-				char32_t character;
-				Utf8Decode(&character, ev.text.text);
-				HandleKeypress(keycode, character);
+				auto [len, c] = DecodeUtf8(ev.text.text);
+				if (len > 0) HandleKeypress(keycode, c);
 			} else {
 				HandleTextInput(ev.text.text);
 			}