diff --git a/exercises/practice/roman-numerals/.meta/example.c b/exercises/practice/roman-numerals/.meta/example.c
index 4f49e79f..f7f160d0 100644
--- a/exercises/practice/roman-numerals/.meta/example.c
+++ b/exercises/practice/roman-numerals/.meta/example.c
@@ -3,7 +3,7 @@
 #include <string.h>
 
 #define NUM_OF_ELEMENTS(a) (sizeof(a) / sizeof(a[0]))
-#define MAX_NUMERAL_LENGTH (10)
+#define MAX_NUMERAL_LENGTH (16)
 
 typedef struct {
    char *numeral;
@@ -18,7 +18,7 @@ const numeral_values_t numeral_values[] = {
 
 char *to_roman_numeral(unsigned int number)
 {
-   char *numerals = calloc(sizeof(char), MAX_NUMERAL_LENGTH);
+   char *numerals = calloc(1, sizeof(char) * (MAX_NUMERAL_LENGTH));
 
    for (size_t i = 0; i < NUM_OF_ELEMENTS(numeral_values); i++) {
       while (number >= numeral_values[i].value) {