diff --git a/addons/purchase/models/purchase.py b/addons/purchase/models/purchase.py
index 96e9a9cecc8..34ba86005dd 100644
--- a/addons/purchase/models/purchase.py
+++ b/addons/purchase/models/purchase.py
@@ -1236,7 +1236,7 @@ class PurchaseOrderLine(models.Model):
             seller = line.product_id._select_seller(
                 partner_id=line.partner_id,
                 quantity=line.product_qty,
-                date=line.order_id.date_order and line.order_id.date_order.date(),
+                date=line.order_id.date_order and line.order_id.date_order.date() or fields.Date.context_today(line),
                 uom_id=line.product_uom,
                 params=params)
 
@@ -1262,14 +1262,14 @@ class PurchaseOrderLine(models.Model):
                     price_unit,
                     line.currency_id,
                     line.company_id,
-                    line.date_order,
+                    line.date_order or fields.Date.context_today(line),
                     False
                 )
                 line.price_unit = float_round(price_unit, precision_digits=max(line.currency_id.decimal_places, self.env['decimal.precision'].precision_get('Product Price')))
                 continue
 
             price_unit = line.env['account.tax']._fix_tax_included_price_company(seller.price, line.product_id.supplier_taxes_id, line.taxes_id, line.company_id) if seller else 0.0
-            price_unit = seller.currency_id._convert(price_unit, line.currency_id, line.company_id, line.date_order, False)
+            price_unit = seller.currency_id._convert(price_unit, line.currency_id, line.company_id, line.date_order or fields.Date.context_today(line), False)
             price_unit = float_round(price_unit, precision_digits=max(line.currency_id.decimal_places, self.env['decimal.precision'].precision_get('Product Price')))
             line.price_unit = seller.product_uom._compute_price(price_unit, line.product_uom)