diff --git a/Form/Type/DataTransformer/DateIntervalTransformer.php b/Form/Type/DataTransformer/DateIntervalTransformer.php
new file mode 100644
index 000000000..29a81447c
--- /dev/null
+++ b/Form/Type/DataTransformer/DateIntervalTransformer.php
@@ -0,0 +1,92 @@
+<?php
+/*
+ * Copyright (C) 2018 Champs Libres Cooperative <info@champs-libres.coop>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+namespace Chill\MainBundle\Form\Type\DataTransformer;
+
+use Symfony\Component\Form\DataTransformerInterface;
+use Symfony\Component\Form\Exception\TransformationFailedException;
+use Symfony\Component\Form\Exception\UnexpectedTypeException;
+
+/**
+ * 
+ *
+ * @author Julien Fastré <julien.fastre@champs-libres.coop>
+ */
+class DateIntervalTransformer implements DataTransformerInterface
+{
+    /**
+     * 
+     * @param \DateInterval $value
+     * @throws UnexpectedTypeException
+     */
+    public function transform($value)
+    {
+        if (empty($value)) {
+            return null;
+        }
+        
+        if (!$value instanceof \DateInterval) {
+            throw new UnexpectedTypeException($value, \DateInterval::class);
+        }
+        
+        if ($value->d > 0) {
+            // we check for weeks (weeks are converted to 7 days)
+            if ($value->d % 7 === 0) {
+                return [
+                    'n' => $value->d / 7,
+                    'unit' => 'W'
+                    ];
+            } else {
+                return [
+                    'n' => $value->d,
+                    'unit' => 'D'
+                ];
+            }
+        } elseif ($value->m > 0) {
+            return [
+                'n' => $value->m,
+                'unit' => 'M'
+            ];
+        } elseif ($value->y > 0) {
+            return [
+                'n' => $value->y,
+                'unit' => 'Y'
+            ];
+        }
+        
+        throw new TransformationFailedException('the date interval does not '
+            . 'contains any days, months or years');
+    }
+
+    public function reverseTransform($value)
+    {
+        if (empty($value) or empty($value['n'])) {
+            return null;
+        }
+        
+        $string = 'P'.$value['n'].$value['unit'];
+        
+        try {
+            return new \DateInterval($string);
+        } catch (\Exception $e) {
+            throw new TransformationFailedException("Could not transform value "
+                . "into DateInterval", 1542, $e);
+        }
+        
+        
+    }
+}
diff --git a/Form/Type/DateIntervalType.php b/Form/Type/DateIntervalType.php
new file mode 100644
index 000000000..499c61f93
--- /dev/null
+++ b/Form/Type/DateIntervalType.php
@@ -0,0 +1,57 @@
+<?php
+/*
+ * Copyright (C) 2018 Champs Libres Cooperative <info@champs-libres.coop>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+namespace Chill\MainBundle\Form\Type;
+
+use Symfony\Component\Form\AbstractType;
+use Symfony\Component\Form\FormBuilderInterface;
+use Symfony\Component\Form\Extension\Core\Type\IntegerType;
+use Symfony\Component\Form\Extension\Core\Type\ChoiceType;
+use Chill\MainBundle\Form\Type\DataTransformer\DateIntervalTransformer;
+use Symfony\Component\Validator\Constraints\GreaterThan;
+
+/**
+ * 
+ *
+ */
+class DateIntervalType extends AbstractType
+{
+    public function buildForm(FormBuilderInterface $builder, array $options)
+    {
+        $builder
+            ->add('n', IntegerType::class, [
+                'scale' => 0,
+                'constraints' => [
+                    new GreaterThan([
+                        'value' => 0
+                    ])
+                ]
+            ])
+            ->add('unit', ChoiceType::class, [
+                'choices' => [
+                    'Days' => 'D',
+                    'Weeks' => 'W',
+                    'Months' => 'M',
+                    'Years' => 'Y'
+                ],
+                'choices_as_values' => true
+            ])
+            ;
+        
+        $builder->addModelTransformer(new DateIntervalTransformer());
+    }
+}