diff --git a/revision.c b/revision.c
index 0ae1c76db3..8cda6e43d4 100644
--- a/revision.c
+++ b/revision.c
@@ -2214,6 +2214,27 @@ static void add_message_grep(struct rev_info *revs, const char *pattern)
 	add_grep(revs, pattern, GREP_PATTERN_BODY);
 }
 
+static int parse_count(const char *arg)
+{
+	int count;
+
+	if (strtol_i(arg, 10, &count) < 0)
+		die("'%s': not an integer", arg);
+	return count;
+}
+
+static timestamp_t parse_age(const char *arg)
+{
+	timestamp_t num;
+	char *p;
+
+	errno = 0;
+	num = parse_timestamp(arg, &p, 10);
+	if (errno || *p || p == arg)
+		die("'%s': not a number of seconds since epoch", arg);
+	return num;
+}
+
 static int handle_revision_opt(struct rev_info *revs, int argc, const char **argv,
 			       int *unkc, const char **unkv,
 			       const struct setup_revision_opt* opt)
@@ -2240,29 +2261,27 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	}
 
 	if ((argcount = parse_long_opt("max-count", argv, &optarg))) {
-		revs->max_count = atoi(optarg);
+		revs->max_count = parse_count(optarg);
 		revs->no_walk = 0;
 		return argcount;
 	} else if ((argcount = parse_long_opt("skip", argv, &optarg))) {
-		revs->skip_count = atoi(optarg);
+		revs->skip_count = parse_count(optarg);
 		return argcount;
 	} else if ((*arg == '-') && isdigit(arg[1])) {
 		/* accept -<digit>, like traditional "head" */
-		if (strtol_i(arg + 1, 10, &revs->max_count) < 0 ||
-		    revs->max_count < 0)
-			die("'%s': not a non-negative integer", arg + 1);
+		revs->max_count = parse_count(arg + 1);
 		revs->no_walk = 0;
 	} else if (!strcmp(arg, "-n")) {
 		if (argc <= 1)
 			return error("-n requires an argument");
-		revs->max_count = atoi(argv[1]);
+		revs->max_count = parse_count(argv[1]);
 		revs->no_walk = 0;
 		return 2;
 	} else if (skip_prefix(arg, "-n", &optarg)) {
-		revs->max_count = atoi(optarg);
+		revs->max_count = parse_count(optarg);
 		revs->no_walk = 0;
 	} else if ((argcount = parse_long_opt("max-age", argv, &optarg))) {
-		revs->max_age = atoi(optarg);
+		revs->max_age = parse_age(optarg);
 		return argcount;
 	} else if ((argcount = parse_long_opt("since", argv, &optarg))) {
 		revs->max_age = approxidate(optarg);
@@ -2274,7 +2293,7 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 		revs->max_age = approxidate(optarg);
 		return argcount;
 	} else if ((argcount = parse_long_opt("min-age", argv, &optarg))) {
-		revs->min_age = atoi(optarg);
+		revs->min_age = parse_age(optarg);
 		return argcount;
 	} else if ((argcount = parse_long_opt("before", argv, &optarg))) {
 		revs->min_age = approxidate(optarg);
@@ -2362,11 +2381,11 @@ static int handle_revision_opt(struct rev_info *revs, int argc, const char **arg
 	} else if (!strcmp(arg, "--no-merges")) {
 		revs->max_parents = 1;
 	} else if (skip_prefix(arg, "--min-parents=", &optarg)) {
-		revs->min_parents = atoi(optarg);
+		revs->min_parents = parse_count(optarg);
 	} else if (!strcmp(arg, "--no-min-parents")) {
 		revs->min_parents = 0;
 	} else if (skip_prefix(arg, "--max-parents=", &optarg)) {
-		revs->max_parents = atoi(optarg);
+		revs->max_parents = parse_count(optarg);
 	} else if (!strcmp(arg, "--no-max-parents")) {
 		revs->max_parents = -1;
 	} else if (!strcmp(arg, "--boundary")) {
diff --git a/t/t6005-rev-list-count.sh b/t/t6005-rev-list-count.sh
index 0729f800c3..ee0306aeec 100755
--- a/t/t6005-rev-list-count.sh
+++ b/t/t6005-rev-list-count.sh
@@ -18,20 +18,34 @@ test_expect_success 'no options' '
 '
 
 test_expect_success '--max-count' '
+	test_must_fail git rev-list --max-count=1q HEAD 2>error &&
+	grep "not an integer" error &&
+
 	test_stdout_line_count = 0 git rev-list HEAD --max-count=0 &&
 	test_stdout_line_count = 3 git rev-list HEAD --max-count=3 &&
 	test_stdout_line_count = 5 git rev-list HEAD --max-count=5 &&
-	test_stdout_line_count = 5 git rev-list HEAD --max-count=10
+	test_stdout_line_count = 5 git rev-list HEAD --max-count=10 &&
+	test_stdout_line_count = 5 git rev-list HEAD --max-count=-1
 '
 
 test_expect_success '--max-count all forms' '
+	test_must_fail git rev-list -1q HEAD 2>error &&
+	grep "not an integer" error &&
+	test_must_fail git rev-list --1 HEAD &&
+	test_must_fail git rev-list -n 1q HEAD 2>error &&
+	grep "not an integer" error &&
+
 	test_stdout_line_count = 1 git rev-list HEAD --max-count=1 &&
 	test_stdout_line_count = 1 git rev-list HEAD -1 &&
 	test_stdout_line_count = 1 git rev-list HEAD -n1 &&
-	test_stdout_line_count = 1 git rev-list HEAD -n 1
+	test_stdout_line_count = 1 git rev-list HEAD -n 1 &&
+	test_stdout_line_count = 5 git rev-list HEAD -n -1
 '
 
 test_expect_success '--skip' '
+	test_must_fail git rev-list --skip 1q HEAD 2>error &&
+	grep "not an integer" error &&
+
 	test_stdout_line_count = 5 git rev-list HEAD --skip=0 &&
 	test_stdout_line_count = 2 git rev-list HEAD --skip=3 &&
 	test_stdout_line_count = 0 git rev-list HEAD --skip=5 &&
diff --git a/t/t6009-rev-list-parent.sh b/t/t6009-rev-list-parent.sh
index 5a67bbc760..9c9a8459af 100755
--- a/t/t6009-rev-list-parent.sh
+++ b/t/t6009-rev-list-parent.sh
@@ -62,6 +62,17 @@ test_expect_success 'setup roots, merges and octopuses' '
 	git checkout main
 '
 
+test_expect_success 'parse --max-parents & --min-parents' '
+	test_must_fail git rev-list --max-parents=1q HEAD 2>error &&
+	grep "not an integer" error &&
+
+	test_must_fail git rev-list --min-parents=1q HEAD 2>error &&
+	grep "not an integer" error &&
+
+	git rev-list --max-parents=1 --min-parents=1 HEAD &&
+	git rev-list --max-parents=-1 --min-parents=-1 HEAD
+'
+
 test_expect_success 'rev-list roots' '
 
 	check_revlist "--max-parents=0" one five