diff --git a/book.py b/book.py
index dd92f35..2adfb4f 100644
--- a/book.py
+++ b/book.py
@@ -76,14 +76,16 @@ class Book(Workflow, ModelSQL, ModelView):
                 ),
         }, depends=DEPENDS+['lines'])
     start_balance = fields.Numeric(string='Initial Amount', required=True,
+        digits=(16, Eval('currency_digits', 2)),
         states={
             'readonly': Or(
                 STATES['readonly'],
                 Bool(Eval('lines')),
                 ),
-        }, depends=DEPENDS+['lines'])
-    balance = fields.Function(fields.Numeric(string='Balance', readonly=True),
-        'on_change_with_balance')
+        }, depends=DEPENDS+['lines', 'currency_digits'])
+    balance = fields.Function(fields.Numeric(string='Balance', readonly=True,
+        digits=(16, Eval('currency_digits', 2)),
+        depends=['currency_digits']), 'on_change_with_balance')
     currency = fields.Many2One(string='Currency', required=True,
         model_name='currency.currency',
         states={
@@ -92,6 +94,8 @@ class Book(Workflow, ModelSQL, ModelView):
                 Bool(Eval('lines', [])),
                 ),
         }, depends=DEPENDS+['lines'])
+    currency_digits = fields.Function(fields.Integer(string='Currency Digits',
+        readonly=True), 'on_change_with_currency_digits')
     state = fields.Selection(string='State', required=True,
         readonly=True, selection=sel_state_book)
     state_string = state.translated('state')
@@ -196,6 +200,15 @@ class Book(Workflow, ModelSQL, ModelView):
             'state': self.state_string,
             }
 
+    @fields.depends('currency')
+    def on_change_with_currency_digits(self, name=None):
+        """ currency of cashbook
+        """
+        if self.currency:
+            return self.currency.digits
+        else:
+            return 2
+
     @fields.depends('id', 'start_balance')
     def on_change_with_balance(self, name=None):
         """ compute balance
diff --git a/locale/de.po b/locale/de.po
index 37bc9fb..b8b5947 100644
--- a/locale/de.po
+++ b/locale/de.po
@@ -462,6 +462,10 @@ msgctxt "field:cashbook.book,currency:"
 msgid "Currency"
 msgstr "Währung"
 
+msgctxt "field:cashbook.book,currency_digits:"
+msgid "Currency Digits"
+msgstr "Nachkommastellen Währung"
+
 msgctxt "field:cashbook.book,start_balance:"
 msgid "Initial Amount"
 msgstr "Anfangsbetrag"