diff --git a/src/main.c b/src/main.c
index 3b52a97f0..2c39d764e 100644
--- a/src/main.c
+++ b/src/main.c
@@ -125,12 +125,21 @@ int main(int argc, char *argv[]) {
     } else if (strcmp(argv[i], "--width") == 0) {
       i += 1;
       if (i < argc) {
+        errno = 0;
         width = (int)strtol(argv[i], &unparsed, 10);
-        if (unparsed && unparsed[0]) {
+        if (errno == ERANGE) {
+          fprintf(stderr, "width value out of range: '%s'\n", argv[i]);
+          exit(1);
+        }
+        if (unparsed == argv[i] || (unparsed && unparsed[0])) {
           fprintf(stderr, "failed parsing width '%s' at '%s'\n", argv[i],
                   unparsed);
           exit(1);
         }
+        if (width < 0) {
+          fprintf(stderr, "width must be >= 0: '%s'\n", argv[i]);
+          exit(1);
+        }
       } else {
         fprintf(stderr, "--width requires an argument\n");
         exit(1);