diff --git a/invoice.odt b/invoice.odt
index d5f8c4c2c6..e7ff20cb22 100644
Binary files a/invoice.odt and b/invoice.odt differ
diff --git a/invoice.py b/invoice.py
index 066302c019..1f5a65be6d 100644
--- a/invoice.py
+++ b/invoice.py
@@ -1243,6 +1243,7 @@ class InvoiceLine(OSV):
         ('comment', 'Comment'),
         ], 'Type', select=1, required=True)
     quantity = fields.Float('Quantity',
+            digits="(16, unit_digits)",
             states={
                 'invisible': "type != 'line'",
                 'required': "type == 'line'",
@@ -1252,6 +1253,8 @@ class InvoiceLine(OSV):
                 'required': "product",
                 'invisible': "type != 'line'",
             }, domain="[('category', '=', (product, 'product'))]")
+    unit_digits = fields.Function('get_unit_digits', type='integer',
+            string='Unit Digits', on_change_with=['unit'])
     product = fields.Many2One('product.product', 'Product',
             states={
                 'invisible': "type != 'line'",
@@ -1329,6 +1332,21 @@ class InvoiceLine(OSV):
                     (vals.get('unit_price') or Decimal('0.0')))
         return Decimal('0.0')
 
+    def on_change_with_unit_digits(self, cursor, user, ids, vals,
+            context=None):
+        uom_obj = self.pool.get('product.uom')
+        if vals.get('unit'):
+            uom = uom_obj.browse(cursor, user, vals['unit'],
+                    context=context)
+            return uom.digits
+        return 2
+
+    def get_unit_digits(self, cursor, user, ids, name, arg, context=None):
+        res = {}
+        for line in self.browse(cursor, user, ids, context=context):
+            res[line.id] = line.unit.digits
+        return res
+
     def get_amount(self, cursor, user, ids, name, arg, context=None):
         currency_obj = self.pool.get('currency.currency')
         res = {}
diff --git a/invoice.xml b/invoice.xml
index c70f371b9d..505e0ef0cb 100644
--- a/invoice.xml
+++ b/invoice.xml
@@ -199,6 +199,7 @@
                                     <field name="taxes"/>
                                     <field name="amount"/>
                                     <field name="sequence" tree_invisible="1"/>
+                                    <field name="unit_digits" tree_invisible="1"/>
                                 </tree>
                             </field>
                             <group col="1" colspan="2">
@@ -529,6 +530,7 @@
                     <field name="amount"/>
                     <separator name="taxes" colspan="4"/>
                     <field name="taxes" colspan="4"/>
+                    <field name="unit_digits" invisible="1"/>
                 </form>
                 ]]>
             </field>
@@ -549,6 +551,7 @@
                     <field name="unit_price" select="2"/>
                     <field name="taxes"/>
                     <field name="amount"/>
+                    <field name="unit_digits" tree_invisible="1"/>
                 </tree>
                 ]]>
             </field>