diff --git a/luna/include/luna/Format.h b/luna/include/luna/Format.h
index 245979a7..e1cccc3c 100644
--- a/luna/include/luna/Format.h
+++ b/luna/include/luna/Format.h
@@ -6,5 +6,5 @@
 typedef Result<void> (*callback_t)(char, void*);
 
 Result<usize> cstyle_format(const char* format, callback_t callback, void* arg, va_list ap);
-Result<usize> vstring_format(char* buf, size_t max, const char* format, va_list ap);
-Result<usize> string_format(char* buf, size_t max, const char* format, ...);
\ No newline at end of file
+Result<usize> vstring_format(char* buf, usize max, const char* format, va_list ap);
+Result<usize> string_format(char* buf, usize max, const char* format, ...);
\ No newline at end of file
diff --git a/luna/src/Format.cpp b/luna/src/Format.cpp
index 5bb9cb1e..ccdde3ab 100644
--- a/luna/src/Format.cpp
+++ b/luna/src/Format.cpp
@@ -475,10 +475,10 @@ Result<usize> cstyle_format(const char* format, callback_t callback, void* arg,
 struct StringFormatInfo
 {
     char* buffer;
-    size_t remaining;
+    usize remaining;
 };
 
-Result<usize> vstring_format(char* buf, size_t max, const char* format, va_list ap)
+Result<usize> vstring_format(char* buf, usize max, const char* format, va_list ap)
 {
     StringFormatInfo info = {.buffer = buf, .remaining = max - 1};
 
@@ -499,7 +499,7 @@ Result<usize> vstring_format(char* buf, size_t max, const char* format, va_list
     return result;
 }
 
-Result<usize> string_format(char* buf, size_t max, const char* format, ...)
+Result<usize> string_format(char* buf, usize max, const char* format, ...)
 {
     va_list ap;
     va_start(ap, format);