diff --git a/src/repart/repart.c b/src/repart/repart.c
index 7a8bc00919..1cdc0a051f 100644
--- a/src/repart/repart.c
+++ b/src/repart/repart.c
@@ -1133,16 +1133,16 @@ static uint64_t partition_min_size(const Context *context, const Partition *p) {
                 uint64_t d = 0;
 
                 if (p->encrypt != ENCRYPT_OFF)
-                        d += round_up_size(LUKS2_METADATA_KEEP_FREE, context->grain_size);
+                        assert_se(INC_SAFE(&d, round_up_size(LUKS2_METADATA_KEEP_FREE, context->grain_size)));
 
                 if (p->copy_blocks_size != UINT64_MAX)
-                        d += round_up_size(p->copy_blocks_size, context->grain_size);
+                        assert_se(INC_SAFE(&d, round_up_size(p->copy_blocks_size, context->grain_size)));
                 else if (p->format || p->encrypt != ENCRYPT_OFF) {
                         uint64_t f;
 
                         /* If we shall synthesize a file system, take minimal fs size into account (assumed to be 4K if not known) */
                         f = partition_fstype_min_size(context, p);
-                        d += f == UINT64_MAX ? context->grain_size : round_up_size(f, context->grain_size);
+                        assert_se(INC_SAFE(&d, f == UINT64_MAX ? context->grain_size : round_up_size(f, context->grain_size)));
                 }
 
                 if (d > sz)