diff --git a/re2o/utils.py b/re2o/utils.py
index 5a4f9400..75304369 100644
--- a/re2o/utils.py
+++ b/re2o/utils.py
@@ -44,6 +44,49 @@ from cotisations.models import Cotisation, Facture, Vente
 from machines.models import Interface, Machine
 from users.models import Adherent, User, Ban, Whitelist
 
+# Mapping of srtftime format for better understanding
+# https://docs.python.org/3.6/library/datetime.html#strftime-strptime-behavior
+datetime_mapping={
+    '%a': '%a',
+    '%A': '%A',
+    '%w': '%w',
+    '%d': 'dd',
+    '%b': '%b',
+    '%B': '%B',
+    '%m': 'mm',
+    '%y': 'yy',
+    '%Y': 'yyyy',
+    '%H': 'HH',
+    '%I': 'HH(12h)',
+    '%p': 'AMPM',
+    '%M': 'MM',
+    '%S': 'SS',
+    '%f': 'µµ',
+    '%z': 'UTC(+/-HHMM)',
+    '%Z': 'UTC(TZ)',
+    '%j': '%j',
+    '%U': 'ww',
+    '%W': 'ww',
+    '%c': '%c',
+    '%x': '%x',
+    '%X': '%X',
+    '%%': '%%',
+}
+
+
+def convert_datetime_format(format):
+    i=0
+    new_format = ""
+    while i < len(format):
+        if format[i] == '%':
+            char = format[i:i+2]
+            new_format += datetime_mapping.get(char, char)
+            i += 2
+        else:
+            new_format += format[i]
+            i += 1
+    return new_format
+
 
 def all_adherent(search_time=None):
     """ Fonction renvoyant tous les users adherents. Optimisee pour n'est
@@ -318,3 +361,19 @@ def remove_user_room(room):
         return
     user.room = None
     user.save()
+
+
+def get_input_formats_help_text(input_formats):
+    """Returns a help text about the possible input formats"""
+    if len(input_formats) > 1:
+        help_text_template="Format: {main} {more}"
+    else:
+        help_text_template="Format: {main}"
+    more_text_template="<i class=\"fa fa-question-circle\" title=\"{}\"></i>"
+    help_text = help_text_template.format(
+        main=convert_datetime_format(input_formats[0]),
+        more=more_text_template.format(
+            '\n'.join(map(convert_datetime_format, input_formats))
+        )
+    )
+    return help_text
diff --git a/search/forms.py b/search/forms.py
index b0668ef9..8cdb1cc1 100644
--- a/search/forms.py
+++ b/search/forms.py
@@ -26,6 +26,7 @@ from __future__ import unicode_literals
 
 from django import forms
 from django.forms import Form
+from re2o.utils import get_input_formats_help_text
 
 CHOICES_USER = (
     ('0', 'Actifs'),
@@ -91,12 +92,17 @@ class SearchFormPlus(Form):
     s = forms.DateField(
         required=False,
         label="Date de début",
-        help_text='DD/MM/YYYY',
-        input_formats=['%d/%m/%Y']
     )
     e = forms.DateField(
         required=False,
-        help_text='DD/MM/YYYY',
-        input_formats=['%d/%m/%Y'],
         label="Date de fin"
     )
+
+    def __init__(self, *args, **kwargs):
+        super(SearchFormPlus, self).__init__(*args, **kwargs)
+        self.fields['s'].help_text = get_input_formats_help_text(
+            self.fields['s'].input_formats
+        )
+        self.fields['e'].help_text = get_input_formats_help_text(
+            self.fields['e'].input_formats
+        )
diff --git a/users/forms.py b/users/forms.py
index 383ef9e8..03571fc3 100644
--- a/users/forms.py
+++ b/users/forms.py
@@ -41,7 +41,7 @@ from django.utils import timezone
 from django.contrib.auth.models import Group, Permission
 
 from preferences.models import OptionalUser
-from re2o.utils import remove_user_room
+from re2o.utils import remove_user_room, get_input_formats_help_text
 from re2o.mixins import FormRevMixin
 from re2o.field_permissions import FieldPermissionFormMixin
 
@@ -565,6 +565,9 @@ class BanForm(FormRevMixin, ModelForm):
         prefix = kwargs.pop('prefix', self.Meta.model.__name__)
         super(BanForm, self).__init__(*args, prefix=prefix, **kwargs)
         self.fields['date_end'].label = 'Date de fin'
+        self.fields['date_end'].help_text = get_input_formats_help_text(
+            self.fields['date_end'].input_formats
+        )
 
     class Meta:
         model = Ban
@@ -577,6 +580,9 @@ class WhitelistForm(FormRevMixin, ModelForm):
         prefix = kwargs.pop('prefix', self.Meta.model.__name__)
         super(WhitelistForm, self).__init__(*args, prefix=prefix, **kwargs)
         self.fields['date_end'].label = 'Date de fin'
+        self.fields['date_end'].help_text = get_input_formats_help_text(
+            self.fields['date_end'].input_formats
+        )
 
     class Meta:
         model = Whitelist
diff --git a/users/migrations/0072_auto_20180426_2021.py b/users/migrations/0072_auto_20180426_2021.py
new file mode 100644
index 00000000..f60103e0
--- /dev/null
+++ b/users/migrations/0072_auto_20180426_2021.py
@@ -0,0 +1,25 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.10.7 on 2018-04-26 18:21
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('users', '0071_auto_20180415_1252'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='ban',
+            name='date_end',
+            field=models.DateTimeField(),
+        ),
+        migrations.AlterField(
+            model_name='whitelist',
+            name='date_end',
+            field=models.DateTimeField(),
+        ),
+    ]
diff --git a/users/models.py b/users/models.py
index f7bfc128..0b89986e 100644
--- a/users/models.py
+++ b/users/models.py
@@ -1229,7 +1229,7 @@ class Ban(RevMixin, AclMixin, models.Model):
     user = models.ForeignKey('User', on_delete=models.PROTECT)
     raison = models.CharField(max_length=255)
     date_start = models.DateTimeField(auto_now_add=True)
-    date_end = models.DateTimeField(help_text='%d/%m/%y %H:%M:%S')
+    date_end = models.DateTimeField()
     state = models.IntegerField(choices=STATES, default=STATE_HARD)
 
     class Meta:
@@ -1314,7 +1314,7 @@ class Whitelist(RevMixin, AclMixin, models.Model):
     user = models.ForeignKey('User', on_delete=models.PROTECT)
     raison = models.CharField(max_length=255)
     date_start = models.DateTimeField(auto_now_add=True)
-    date_end = models.DateTimeField(help_text='%d/%m/%y %H:%M:%S')
+    date_end = models.DateTimeField()
 
     class Meta:
         permissions = (