diff --git a/include/libopencm3/stm32/can.h b/include/libopencm3/stm32/can.h
index d6636d5f..cdb5df19 100644
--- a/include/libopencm3/stm32/can.h
+++ b/include/libopencm3/stm32/can.h
@@ -458,7 +458,7 @@
 /* --- CAN_TIxR values ------------------------------------------------------ */
 
 /* STID[10:0]: Standard identifier */
-#define CAN_TIxR_STID_MASK		(0x3FF << 21)
+#define CAN_TIxR_STID_MASK		(0x7FF << 21)
 #define CAN_TIxR_STID_SHIFT		21
 
 /* EXID[15:0]: Extended identifier */