diff --git a/add-interactive.c b/add-interactive.c
index 9b8cdb4..09faee0 100644
--- a/add-interactive.c
+++ b/add-interactive.c
@@ -413,7 +413,7 @@ struct file_item {
 
 static void add_file_item(struct string_list *files, const char *name)
 {
-	struct file_item *item = xcalloc(sizeof(*item), 1);
+	struct file_item *item = xcalloc(1, sizeof(*item));
 
 	string_list_append(files, name)->util = item;
 }
@@ -476,7 +476,7 @@ static void collect_changes_cb(struct diff_queue_struct *q,
 
 			add_file_item(s->files, name);
 
-			entry = xcalloc(sizeof(*entry), 1);
+			entry = xcalloc(1, sizeof(*entry));
 			hashmap_entry_init(&entry->ent, hash);
 			entry->name = s->files->items[s->files->nr - 1].string;
 			entry->item = s->files->items[s->files->nr - 1].util;
@@ -1120,7 +1120,7 @@ int run_add_i(struct repository *r, const struct pathspec *ps)
 	int res = 0;
 
 	for (i = 0; i < ARRAY_SIZE(command_list); i++) {
-		struct command_item *util = xcalloc(sizeof(*util), 1);
+		struct command_item *util = xcalloc(1, sizeof(*util));
 		util->command = command_list[i].command;
 		string_list_append(&commands.items, command_list[i].string)
 			->util = util;
diff --git a/blame.c b/blame.c
index a5044fc..d6a3f5b 100644
--- a/blame.c
+++ b/blame.c
@@ -951,13 +951,13 @@ static int *fuzzy_find_matching_lines(struct blame_origin *parent,
 	max_search_distance_b = ((2 * max_search_distance_a + 1) * length_b
 				 - 1) / length_a;
 
-	result = xcalloc(sizeof(int), length_b);
-	second_best_result = xcalloc(sizeof(int), length_b);
-	certainties = xcalloc(sizeof(int), length_b);
+	result = xcalloc(length_b, sizeof(int));
+	second_best_result = xcalloc(length_b, sizeof(int));
+	certainties = xcalloc(length_b, sizeof(int));
 
 	/* See get_similarity() for details of similarities. */
 	similarity_count = length_b * (max_search_distance_a * 2 + 1);
-	similarities = xcalloc(sizeof(int), similarity_count);
+	similarities = xcalloc(similarity_count, sizeof(int));
 
 	for (i = 0; i < length_b; ++i) {
 		result[i] = -1;
@@ -995,7 +995,7 @@ static void fill_origin_fingerprints(struct blame_origin *o)
 		return;
 	o->num_lines = find_line_starts(&line_starts, o->file.ptr,
 					o->file.size);
-	o->fingerprints = xcalloc(sizeof(struct fingerprint), o->num_lines);
+	o->fingerprints = xcalloc(o->num_lines, sizeof(struct fingerprint));
 	get_line_fingerprints(o->fingerprints, o->file.ptr, line_starts,
 			      0, o->num_lines);
 	free(line_starts);
@@ -1853,8 +1853,8 @@ static void blame_chunk(struct blame_entry ***dstq, struct blame_entry ***srcq,
 	diffp = NULL;
 
 	if (ignore_diffs && same - tlno > 0) {
-		line_blames = xcalloc(sizeof(struct blame_line_tracker),
-				      same - tlno);
+		line_blames = xcalloc(same - tlno,
+				      sizeof(struct blame_line_tracker));
 		guess_line_blames(parent, target, tlno, offset, same,
 				  parent_len, line_blames);
 	}
diff --git a/contrib/coccinelle/xcalloc.cocci b/contrib/coccinelle/xcalloc.cocci
new file mode 100644
index 0000000..c291011
--- /dev/null
+++ b/contrib/coccinelle/xcalloc.cocci
@@ -0,0 +1,10 @@
+@@
+type T;
+T *ptr;
+expression n;
+@@
+  xcalloc(
++ n,
+  \( sizeof(T) \| sizeof(*ptr) \)
+- , n
+  )
diff --git a/range-diff.c b/range-diff.c
index b9950f1..dfc20ad 100644
--- a/range-diff.c
+++ b/range-diff.c
@@ -93,7 +93,7 @@ static int read_patches(const char *range, struct string_list *list,
 				string_list_append(list, buf.buf)->util = util;
 				strbuf_reset(&buf);
 			}
-			util = xcalloc(sizeof(*util), 1);
+			util = xcalloc(1, sizeof(*util));
 			if (get_oid(p, &util->oid)) {
 				error(_("could not parse commit '%s'"), p);
 				free(util);
diff --git a/ref-filter.c b/ref-filter.c
index ee337df..033cd4f 100644
--- a/ref-filter.c
+++ b/ref-filter.c
@@ -768,7 +768,8 @@ static int if_atom_handler(struct atom_value *atomv, struct ref_formatting_state
 			   struct strbuf *unused_err)
 {
 	struct ref_formatting_stack *new_stack;
-	struct if_then_else *if_then_else = xcalloc(sizeof(struct if_then_else), 1);
+	struct if_then_else *if_then_else = xcalloc(1,
+						    sizeof(struct if_then_else));
 
 	if_then_else->str = atomv->atom->u.if_then_else.str;
 	if_then_else->cmp_status = atomv->atom->u.if_then_else.cmp_status;
@@ -2242,7 +2243,7 @@ static void reach_filter(struct ref_array *array,
 	if (!check_reachable)
 		return;
 
-	to_clear = xcalloc(sizeof(struct commit *), array->nr);
+	to_clear = xcalloc(array->nr, sizeof(struct commit *));
 
 	repo_init_revisions(the_repository, &revs, NULL);
 
diff --git a/trailer.c b/trailer.c
index 3f7391d..61ffbf6 100644
--- a/trailer.c
+++ b/trailer.c
@@ -174,7 +174,7 @@ static void print_all(FILE *outfile, struct list_head *head,
 
 static struct trailer_item *trailer_from_arg(struct arg_item *arg_tok)
 {
-	struct trailer_item *new_item = xcalloc(sizeof(*new_item), 1);
+	struct trailer_item *new_item = xcalloc(1, sizeof(*new_item));
 	new_item->token = arg_tok->token;
 	new_item->value = arg_tok->value;
 	arg_tok->token = arg_tok->value = NULL;
@@ -445,7 +445,7 @@ static struct arg_item *get_conf_item(const char *name)
 	}
 
 	/* Item does not already exists, create it */
-	item = xcalloc(sizeof(*item), 1);
+	item = xcalloc(1, sizeof(*item));
 	duplicate_conf(&item->conf, &default_conf_info);
 	item->conf.name = xstrdup(name);
 
@@ -664,7 +664,7 @@ static void parse_trailer(struct strbuf *tok, struct strbuf *val,
 static struct trailer_item *add_trailer_item(struct list_head *head, char *tok,
 					     char *val)
 {
-	struct trailer_item *new_item = xcalloc(sizeof(*new_item), 1);
+	struct trailer_item *new_item = xcalloc(1, sizeof(*new_item));
 	new_item->token = tok;
 	new_item->value = val;
 	list_add_tail(&new_item->list, head);
@@ -675,7 +675,7 @@ static void add_arg_item(struct list_head *arg_head, char *tok, char *val,
 			 const struct conf_info *conf,
 			 const struct new_trailer_item *new_trailer_item)
 {
-	struct arg_item *new_item = xcalloc(sizeof(*new_item), 1);
+	struct arg_item *new_item = xcalloc(1, sizeof(*new_item));
 	new_item->token = tok;
 	new_item->value = val;
 	duplicate_conf(&new_item->conf, conf);