diff --git a/subsys/bluetooth/controller/ll_sw/ull_scan.c b/subsys/bluetooth/controller/ll_sw/ull_scan.c
index ef538ff97b7..f0147d9cb35 100644
--- a/subsys/bluetooth/controller/ll_sw/ull_scan.c
+++ b/subsys/bluetooth/controller/ll_sw/ull_scan.c
@@ -748,22 +748,18 @@ static uint8_t duration_period_setup(struct ll_scan_set *scan,
 
 	lll = &scan->lll;
 	if (duration) {
-		lll->duration_reload = ((uint32_t)duration *
-					EXT_SCAN_DURATION_UNIT_US /
-					SCAN_INTERVAL_UNIT_US) /
-					scan->lll.interval;
+		lll->duration_reload =
+			ULL_SCAN_DURATION_TO_EVENTS(duration,
+						    scan->lll.interval);
 		if (period) {
 			if (IS_ENABLED(CONFIG_BT_CTLR_PARAM_CHECK) &&
-			    (duration >= ((uint32_t)period *
-					  EXT_SCAN_PERIOD_UNIT_US/
-					  EXT_SCAN_DURATION_UNIT_US))) {
+			    (duration >= ULL_SCAN_PERIOD_TO_DURATION(period))) {
 				return BT_HCI_ERR_INVALID_PARAM;
 			}
 
-			scan->duration_lazy = ((uint32_t)period *
-					       EXT_SCAN_PERIOD_UNIT_US /
-					       SCAN_INTERVAL_UNIT_US) /
-					      scan->lll.interval;
+			scan->duration_lazy =
+				ULL_SCAN_PERIOD_TO_EVENTS(period,
+							  scan->lll.interval);
 			scan->duration_lazy -= lll->duration_reload;
 			scan->node_rx_scan_term = NULL;
 		} else {
diff --git a/subsys/bluetooth/controller/ll_sw/ull_scan_internal.h b/subsys/bluetooth/controller/ll_sw/ull_scan_internal.h
index e785f839aad..c2012d6d54e 100644
--- a/subsys/bluetooth/controller/ll_sw/ull_scan_internal.h
+++ b/subsys/bluetooth/controller/ll_sw/ull_scan_internal.h
@@ -13,6 +13,21 @@
 #define EXT_SCAN_DURATION_UNIT_US 10000U
 #define EXT_SCAN_PERIOD_UNIT_US   1280000U
 
+/* Convert period in 1.28 s units to duration of 10 ms units*/
+#define ULL_SCAN_PERIOD_TO_DURATION(period) \
+	((uint32_t)(period) * EXT_SCAN_PERIOD_UNIT_US / \
+	 EXT_SCAN_DURATION_UNIT_US)
+
+/* Convert duration in 10 ms unit to radio events count */
+#define ULL_SCAN_DURATION_TO_EVENTS(duration, interval) \
+	(((uint32_t)(duration) * EXT_SCAN_DURATION_UNIT_US / \
+	  SCAN_INTERVAL_UNIT_US) / (interval))
+
+/* Convert period in 1.28 s unit to radio events count */
+#define ULL_SCAN_PERIOD_TO_EVENTS(period, interval) \
+	(((uint32_t)(period) * EXT_SCAN_PERIOD_UNIT_US / \
+	  SCAN_INTERVAL_UNIT_US) / (interval))
+
 int ull_scan_init(void);
 int ull_scan_reset(void);