diff --git a/add-patch.c b/add-patch.c
index 302e6ba7d9a353..bcc2d7666ff872 100644
--- a/add-patch.c
+++ b/add-patch.c
@@ -956,6 +956,7 @@ static int split_hunk(struct add_p_state *s, struct file_diff *file_diff,
 			* sizeof(*hunk));
 	hunk = file_diff->hunk + hunk_index;
 	hunk->splittable_into = 1;
+	hunk->use = UNDECIDED_HUNK;
 	memset(hunk + 1, 0, (splittable_into - 1) * sizeof(*hunk));
 
 	header = &hunk->header;
@@ -1057,7 +1058,7 @@ static int split_hunk(struct add_p_state *s, struct file_diff *file_diff,
 
 		hunk++;
 		hunk->splittable_into = 1;
-		hunk->use = hunk[-1].use;
+		hunk->use = UNDECIDED_HUNK;
 		header = &hunk->header;
 
 		header->old_count = header->new_count = context_line_count;
@@ -1184,19 +1185,29 @@ static ssize_t recount_edited_hunk(struct add_p_state *s, struct hunk *hunk,
 {
 	struct hunk_header *header = &hunk->header;
 	size_t i;
+	char ch, marker = ' ';
 
+	hunk->splittable_into = 0;
 	header->old_count = header->new_count = 0;
 	for (i = hunk->start; i < hunk->end; ) {
-		switch(normalize_marker(&s->plain.buf[i])) {
+		ch = normalize_marker(&s->plain.buf[i]);
+		switch (ch) {
 		case '-':
 			header->old_count++;
+			if (marker == ' ')
+				hunk->splittable_into++;
+			marker = ch;
 			break;
 		case '+':
 			header->new_count++;
+			if (marker == ' ')
+				hunk->splittable_into++;
+			marker = ch;
 			break;
 		case ' ':
 			header->old_count++;
 			header->new_count++;
+			marker = ch;
 			break;
 		}
 
diff --git a/t/t3701-add-interactive.sh b/t/t3701-add-interactive.sh
index 04d2a198352531..13739a45820241 100755
--- a/t/t3701-add-interactive.sh
+++ b/t/t3701-add-interactive.sh
@@ -1301,4 +1301,35 @@ do
 	'
 done
 
+test_expect_success 'splitting previous hunk marks split hunks as undecided' '
+	test_write_lines a " " b c d e f g h i j k >file &&
+	git add file &&
+	test_write_lines x " " b y d e f g h i j x >file &&
+	test_write_lines n K s n y q | git add -p file &&
+	git cat-file blob :file >actual &&
+	test_write_lines a " " b y d e f g h i j k >expect &&
+	test_cmp expect actual
+'
+
+test_expect_success 'splitting edited hunk' '
+	# Before the first hunk is edited it can be split into two
+	# hunks, after editing it can be split into three hunks.
+
+	write_script fake-editor.sh <<-\EOF &&
+	sed "s/^ c/-c/" "$1" >"$1.tmp" &&
+	mv "$1.tmp" "$1"
+	EOF
+
+	test_write_lines a b c d e f g h i j k l m n >file &&
+	git add file &&
+	test_write_lines A b c d E f g h i j k l M n >file &&
+	(
+		test_set_editor "$(pwd)/fake-editor.sh" &&
+		test_write_lines e K s j y n y q | git add -p file
+	) &&
+	git cat-file blob :file >actual &&
+	test_write_lines a b d e f g h i j k l M n >expect &&
+	test_cmp expect actual
+'
+
 test_done