diff --git a/cashonly/core/admin.py b/cashonly/core/admin.py
index 6773aa0..f8ce117 100644
--- a/cashonly/core/admin.py
+++ b/cashonly/core/admin.py
@@ -32,12 +32,13 @@ class AccountForm(forms.ModelForm):
 
 
 class AccountAdmin(admin.ModelAdmin):
-    list_display = ('user', 'card_number', 'credit', 'transaction_link')
+    list_display = ('user', 'card_number', 'credit', 'debit_limit',
+                    'transaction_link')
     form = AccountForm
     readonly_fields = ('user', 'credit',)
     fieldsets = (
         (None, {
-            'fields': ('user', 'card_number', 'credit'),
+            'fields': ('user', 'card_number', 'credit', 'debit_limit'),
         }),
         (ugettext_lazy('credit change'), {
             'fields': ('credit_change', 'credit_change_comment'),
diff --git a/cashonly/core/migrations/0003_debit_limit_null_default.py b/cashonly/core/migrations/0003_debit_limit_null_default.py
new file mode 100644
index 0000000..57e839f
--- /dev/null
+++ b/cashonly/core/migrations/0003_debit_limit_null_default.py
@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.20 on 2019-02-17 21:54
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('cashonly_core', '0002_account_debit_limit'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='account',
+            name='debit_limit',
+            field=models.DecimalField(blank=True, decimal_places=2, default=None, max_digits=5, null=True, verbose_name='debit limit'),
+        ),
+    ]
diff --git a/cashonly/core/models.py b/cashonly/core/models.py
index bab75a3..6569741 100644
--- a/cashonly/core/models.py
+++ b/cashonly/core/models.py
@@ -35,7 +35,9 @@ class Account(models.Model):
         verbose_name=_('debit limit'),
         max_digits=5,
         decimal_places=2,
-        default=settings.CASHONLY_DEFAULT_DEBIT_LIMIT,
+        default=None,
+        blank=True,
+        null=True,
     )
 
     def __str__(self):
diff --git a/cashonly/core/services.py b/cashonly/core/services.py
index caba6e4..945038f 100644
--- a/cashonly/core/services.py
+++ b/cashonly/core/services.py
@@ -5,6 +5,7 @@ from django.utils.translation import ugettext_noop
 from django.db.models.signals import pre_save, post_save, pre_delete
 from django.dispatch import receiver
 from django.db import transaction
+from django.conf import settings
 import PIL.Image
 import io
 
@@ -44,7 +45,11 @@ class AccountManager:
 
         total_value = sum(map(lambda p: p.price * products[p],
                               products.keys()))
-        if self.account.credit - total_value >= self.account.debit_limit * -1:
+        if self.account.debit_limit is not None:
+            debit_limit = self.account.debit_limit
+        else:
+            debit_limit = settings.CASHONLY_DEFAULT_DEBIT_LIMIT
+        if self.account.credit - total_value >= debit_limit * -1:
             desc = ''
             for product in products.keys():
                 if not product.active: