diff --git a/file/chunk_file.cpp b/file/chunk_file.cpp
index 6d61f11841..fde65fe970 100644
--- a/file/chunk_file.cpp
+++ b/file/chunk_file.cpp
@@ -219,7 +219,7 @@ void ChunkFile::writeWString(const std::string &str) {
 	unsigned short *text;
 	size_t len = str.length();
 	text = new unsigned short[len+1];
-	for (int i=0; i<len; i++)
+	for (size_t i=0; i<len; i++)
 		text[i]=str[i];
 	text[len]=0;
 	writeInt(len);
diff --git a/math/expression_parser.cpp b/math/expression_parser.cpp
index d95f4f0b23..c80981c0c0 100644
--- a/math/expression_parser.cpp
+++ b/math/expression_parser.cpp
@@ -367,7 +367,7 @@ bool initPostfixExpression(const char* infix, IExpressionFunctions* funcs, Postf
 
 bool parsePostfixExpression(PostfixExpression& exp, IExpressionFunctions* funcs, uint32& dest)
 {
-	int num = 0;
+	size_t num = 0;
 	uint32 opcode;
 	std::vector<uint32> valueStack;
 	unsigned int arg[5];
diff --git a/util/text/utf8.cpp b/util/text/utf8.cpp
index 378fd236c6..c236125b04 100644
--- a/util/text/utf8.cpp
+++ b/util/text/utf8.cpp
@@ -362,7 +362,7 @@ const char *u8_strchr(const char *s, uint32_t ch, int *charn)
 
 const char *u8_memchr(const char *s, uint32_t ch, size_t sz, int *charn)
 {
-  int i = 0, lasti=0;
+  size_t i = 0, lasti=0;
   uint32_t c;
   int csz;