diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 232ed4bb8fcac..bced6876de791 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -2750,8 +2750,7 @@ struct spi_replaced_transfers *spi_replace_transfers(
 
 	/* allocate the structure using spi_res */
 	rxfer = spi_res_alloc(msg->spi, __spi_replace_transfers_release,
-			      insert * sizeof(struct spi_transfer)
-			      + sizeof(struct spi_replaced_transfers)
+			      struct_size(rxfer, inserted_transfers, insert)
 			      + extradatasize,
 			      gfp);
 	if (!rxfer)