diff --git a/lib/iot/zoap/zoap.c b/lib/iot/zoap/zoap.c
index 2e2d90d9e5f..9b8990655c9 100644
--- a/lib/iot/zoap/zoap.c
+++ b/lib/iot/zoap/zoap.c
@@ -78,7 +78,7 @@ static int decode_delta(int num, const uint8_t *buf, int16_t buflen,
 			return -EINVAL;
 		}
 
-		num = sys_be16_to_cpu((uint16_t)*buf) + 269;
+		num = sys_get_be16(buf) + 269;
 		hdrlen += 2;
 		break;
 	case 15: