diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 54db1184a0..13ed944d2d 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -131,7 +131,7 @@ struct expand_data {
 	unsigned char sha1[20];
 	enum object_type type;
 	unsigned long size;
-	unsigned long disk_size;
+	off_t disk_size;
 	const char *rest;
 	unsigned char delta_base_sha1[20];
 
@@ -184,7 +184,7 @@ static void expand_atom(struct strbuf *sb, const char *atom, int len,
 		if (data->mark_query)
 			data->info.disk_sizep = &data->disk_size;
 		else
-			strbuf_addf(sb, "%lu", data->disk_size);
+			strbuf_addf(sb, "%"PRIuMAX, (uintmax_t)data->disk_size);
 	} else if (is_atom("rest", atom, len)) {
 		if (data->mark_query)
 			data->split_on_whitespace = 1;
diff --git a/cache.h b/cache.h
index 4ff196c259..ea64b51846 100644
--- a/cache.h
+++ b/cache.h
@@ -1502,7 +1502,7 @@ struct object_info {
 	/* Request */
 	enum object_type *typep;
 	unsigned long *sizep;
-	unsigned long *disk_sizep;
+	off_t *disk_sizep;
 	unsigned char *delta_base_sha1;
 	struct strbuf *typename;