diff --git a/drivers/serial/uart_stm32.c b/drivers/serial/uart_stm32.c
index bad6c6fa027..b1fda987c7c 100644
--- a/drivers/serial/uart_stm32.c
+++ b/drivers/serial/uart_stm32.c
@@ -923,14 +923,14 @@ void uart_stm32_dma_tx_cb(const struct device *dma_dev, void *user_data,
 
 	(void)k_work_cancel_delayable(&data->dma_tx.timeout_work);
 
-	data->dma_tx.buffer_length = 0;
-
 	if (!dma_get_status(data->dma_tx.dma_dev,
 				data->dma_tx.dma_channel, &stat)) {
 		data->dma_tx.counter = data->dma_tx.buffer_length -
 					stat.pending_length;
 	}
 
+	data->dma_tx.buffer_length = 0;
+
 	irq_unlock(key);
 }