diff --git a/dump/dump.c b/dump/dump.c
index b043337bc7..d82cc46d7d 100644
--- a/dump/dump.c
+++ b/dump/dump.c
@@ -1548,25 +1548,19 @@ bool qemu_system_dump_in_progress(void)
     return (qatomic_read(&state->status) == DUMP_STATUS_ACTIVE);
 }
 
-/* calculate total size of memory to be dumped (taking filter into
- * acoount.) */
+/*
+ * calculate total size of memory to be dumped (taking filter into
+ * account.)
+ */
 static int64_t dump_calculate_size(DumpState *s)
 {
     GuestPhysBlock *block;
-    int64_t size = 0, total = 0, left = 0, right = 0;
+    int64_t total = 0;
 
     QTAILQ_FOREACH(block, &s->guest_phys_blocks.head, next) {
-        if (dump_has_filter(s)) {
-            /* calculate the overlapped region. */
-            left = MAX(s->filter_area_begin, block->target_start);
-            right = MIN(s->filter_area_begin + s->filter_area_length, block->target_end);
-            size = right - left;
-            size = size > 0 ? size : 0;
-        } else {
-            /* count the whole region in */
-            size = (block->target_end - block->target_start);
-        }
-        total += size;
+        total += dump_filtered_memblock_size(block,
+                                             s->filter_area_begin,
+                                             s->filter_area_length);
     }
 
     return total;