diff --git a/pgrep.c b/pgrep.c
index ce8ccae9..9887402d 100644
--- a/pgrep.c
+++ b/pgrep.c
@@ -54,6 +54,12 @@
 #include "proc/devname.h"
 #include "proc/sysinfo.h"
 
+#define grow_size(x) do { \
+	if ((x) < 0 || (size_t)(x) >= INT_MAX / 5 / sizeof(struct el)) \
+		xerrx(EXIT_FAILURE, _("integer overflow")); \
+	(x) = (x) * 5 / 4 + 4; \
+} while (0)
+
 static int i_am_pkill = 0;
 
 struct el {
@@ -158,7 +164,7 @@ static struct el *split_list (const char *restrict str, int (*convert)(const cha
 
 	do {
 		if (i == size) {
-			size = size * 5 / 4 + 4;
+			grow_size(size);
 			/* add 1 because slot zero is a count */
 			list = xrealloc (list, (1 + size) * sizeof *list);
 		}
@@ -600,7 +606,7 @@ static struct el * select_procs (int *num)
 				matches = 0;
 			}
 			if (matches == size) {
-				size = size * 5 / 4 + 4;
+				grow_size(size);
 				list = xrealloc(list, size * sizeof *list);
 			}
 			if (list && (opt_long || opt_longlong || opt_echo)) {
@@ -624,10 +630,8 @@ static struct el * select_procs (int *num)
 
 					// eventually grow output buffer
 					if (matches == size) {
-						size = size * 5 / 4 + 4;
-						list = realloc(list, size * sizeof *list);
-						if (list == NULL)
-							exit (EXIT_FATAL);
+						grow_size(size);
+						list = xrealloc(list, size * sizeof *list);
 					}
 					if (opt_long || opt_longlong) {
 						list[matches].str = xstrdup (cmdoutput);