diff --git a/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt b/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt
index 2f4fea2..947ab4f 100644
--- a/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt
+++ b/app/src/main/java/it/danieleverducci/lunatracker/MainActivity.kt
@@ -12,6 +12,7 @@ import android.view.View
 import android.view.ViewGroup
 import android.widget.AdapterView
 import android.widget.ArrayAdapter
+import android.widget.Button
 import android.widget.EditText
 import android.widget.NumberPicker
 import android.widget.PopupWindow
@@ -330,7 +331,7 @@ class MainActivity : AppCompatActivity() {
         alertDialog.show()
     }
 
-    fun datePickerHelper(time: Long, dateTextView: TextView): Calendar {
+    fun datePickerHelper(time: Long, dateTextView: TextView, onChange: (Long) -> Unit = {}): Calendar {
         dateTextView.text = DateUtils.formatDateTime(time)
 
         val dateTime = Calendar.getInstance()
@@ -349,6 +350,7 @@ class MainActivity : AppCompatActivity() {
                     { _, hour, minute ->
                         dateTime.set(year, month, day, hour, minute)
                         dateTextView.text = DateUtils.formatDateTime(dateTime.time.time / 1000)
+                        onChange.invoke(dateTime.time.time / 1000)
                     },
                     startHour,
                     startMinute,
@@ -371,6 +373,97 @@ class MainActivity : AppCompatActivity() {
         saveLogbook()
     }
 
+    fun addSleepEvent(event: LunaEvent) {
+        askSleepValue(event) { saveEvent(event) }
+    }
+
+    fun askSleepValue(event: LunaEvent, onPositive: () -> Unit) {
+        val d = AlertDialog.Builder(this)
+        val dialogView = layoutInflater.inflate(R.layout.dialog_edit_duration, null)
+        d.setTitle(event.getTypeDescription(this))
+        d.setMessage(event.getDialogMessage(this))
+        d.setView(dialogView)
+
+        val durationTextView = dialogView.findViewById<TextView>(R.id.dialog_date_duration)
+        val durationNowButton = dialogView.findViewById<Button>(R.id.dialog_date_duration_now)
+        val datePicker = dialogView.findViewById<TextView>(R.id.dialog_date_picker)
+        val durationMinus15Button = dialogView.findViewById<Button>(R.id.dialog_date_duration_minus15)
+        val durationMinus5Button = dialogView.findViewById<Button>(R.id.dialog_date_duration_minus5)
+        val durationPlus15Button = dialogView.findViewById<Button>(R.id.dialog_date_duration_plus15)
+        val durationPlus5Button = dialogView.findViewById<Button>(R.id.dialog_date_duration_plus5)
+
+        val currentDurationTextColor = durationTextView.currentTextColor
+        val invalidDurationTextColor = ContextCompat.getColor(this, R.color.danger)
+
+        var duration = event.quantity
+
+        fun isValidTime(timeSeconds: Long, durationSeconds: Int): Boolean {
+            val now = Calendar.getInstance().time.time / 1000
+            return (timeSeconds + durationSeconds) <= now && durationSeconds < (12 * 60 * 60)
+        }
+
+        val onDateChange = { time: Long ->
+            durationTextView.setTextColor(currentDurationTextColor)
+
+            if (duration == 0) {
+                // baby is sleeping
+                durationTextView.text = "💤"
+            } else {
+                durationTextView.text = DateUtils.formatTimeDuration(applicationContext, duration.toLong())
+                if (!isValidTime(time, duration)) {
+                    durationTextView.setTextColor(invalidDurationTextColor)
+                }
+            }
+        }
+
+        val pickedDateTime = datePickerHelper(event.time, datePicker, onDateChange)
+
+        onDateChange(pickedDateTime.time.time / 1000)
+
+        fun adjust(minutes: Int) {
+            duration += minutes * 60
+            if (duration < 0) {
+                duration = 0
+            }
+            onDateChange(pickedDateTime.time.time / 1000)
+        }
+
+        durationMinus15Button.setOnClickListener { adjust(-15) }
+        durationMinus5Button.setOnClickListener { adjust(-5) }
+        durationPlus5Button.setOnClickListener { adjust(5) }
+        durationPlus15Button.setOnClickListener { adjust(15) }
+
+        durationNowButton.setOnClickListener {
+            val now = Calendar.getInstance().time.time / 1000
+            val start = pickedDateTime.time.time / 1000
+            if (now > start) {
+                duration = (now - start).toInt()
+                duration -= duration % 60 // prevent printing of seconds
+                onDateChange(pickedDateTime.time.time / 1000)
+            }
+        }
+
+        d.setPositiveButton(android.R.string.ok) { dialogInterface, i ->
+            val time = pickedDateTime.time.time / 1000
+
+            if (isValidTime(time, duration)) {
+                event.time = time
+                event.quantity = duration
+                onPositive()
+            } else {
+                Toast.makeText(this, R.string.toast_date_error, Toast.LENGTH_SHORT).show()
+            }
+            dialogInterface.dismiss()
+        }
+
+        d.setNegativeButton(android.R.string.cancel) { dialogInterface, i ->
+            dialogInterface.dismiss()
+        }
+
+        val alertDialog = d.create()
+        alertDialog.show()
+    }
+
     fun addAmountEvent(event: LunaEvent) {
         askAmountValue(event, true) { saveEvent(event) }
     }
@@ -643,6 +736,7 @@ class MainActivity : AppCompatActivity() {
                 LunaEvent.TYPE_PUKE -> askAmountValue(event, false, updateValues)
                 LunaEvent.TYPE_TEMPERATURE -> askTemperatureValue(event, false, updateValues)
                 LunaEvent.TYPE_NOTE -> askNotes(event, false, updateValues)
+                LunaEvent.TYPE_SLEEP -> askSleepValue(event, updateValues)
             }
         }
 
@@ -1100,6 +1194,10 @@ class MainActivity : AppCompatActivity() {
                 addAmountEvent(LunaEvent(LunaEvent.TYPE_PUKE))
                 dismiss()
             }
+            contentView.findViewById<View>(R.id.button_sleep).setOnClickListener {
+                addSleepEvent(LunaEvent(LunaEvent.TYPE_SLEEP))
+                dismiss()
+            }
             contentView.findViewById<View>(R.id.button_colic).setOnClickListener {
                 addPlainEvent(LunaEvent(LunaEvent.TYPE_COLIC))
                 dismiss()
diff --git a/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt b/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt
index 1eade79..63e268b 100644
--- a/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt
+++ b/app/src/main/java/it/danieleverducci/lunatracker/entities/LunaEvent.kt
@@ -30,6 +30,7 @@ class LunaEvent: Comparable<LunaEvent> {
         const val TYPE_FOOD = "FOOD"
         const val TYPE_PUKE = "PUKE"
         const val TYPE_BATH = "BATH"
+        const val TYPE_SLEEP = "SLEEP"
     }
 
     private val jo: JSONObject
@@ -111,6 +112,7 @@ class LunaEvent: Comparable<LunaEvent> {
                 TYPE_FOOD -> R.string.event_food_type
                 TYPE_PUKE -> R.string.event_puke_type
                 TYPE_BATH -> R.string.event_bath_type
+                TYPE_SLEEP -> R.string.event_sleep_type
                 else -> R.string.event_unknown_type
             }
         )
@@ -134,6 +136,7 @@ class LunaEvent: Comparable<LunaEvent> {
                 TYPE_FOOD -> R.string.event_food_desc
                 TYPE_PUKE -> R.string.event_puke_desc
                 TYPE_BATH -> R.string.event_bath_desc
+                TYPE_SLEEP -> R.string.event_sleep_desc
                 else -> R.string.event_unknown_desc
             }
         )
@@ -149,6 +152,7 @@ class LunaEvent: Comparable<LunaEvent> {
                 TYPE_DIAPERCHANGE_PEE,
                 TYPE_PUKE -> R.string.log_amount_dialog_description
                 TYPE_WEIGHT -> R.string.log_weight_dialog_description
+                TYPE_SLEEP -> R.string.log_sleep_dialog_description
                 else -> R.string.log_unknown_dialog_description
             }
         )
diff --git a/app/src/main/java/utils/DateUtils.kt b/app/src/main/java/utils/DateUtils.kt
index 50b3c70..6180e33 100644
--- a/app/src/main/java/utils/DateUtils.kt
+++ b/app/src/main/java/utils/DateUtils.kt
@@ -62,10 +62,8 @@ class DateUtils {
                 return format(days, hours, R.string.day_ago, R.string.days_ago, R.string.hour_ago, R.string.hours_ago)
             } else if (hours > 0) {
                 return format(hours, minutes, R.string.hour_ago, R.string.hours_ago, R.string.minute_ago, R.string.minutes_ago)
-            } else if (minutes > 0) {
-                return format(minutes, seconds, R.string.minute_ago, R.string.minute_ago, R.string.second_ago, R.string.seconds_ago)
             } else {
-                return context.getString(R.string.now)
+                return format(minutes, seconds, R.string.minute_ago, R.string.minute_ago, R.string.second_ago, R.string.seconds_ago)
             }
         }
 
diff --git a/app/src/main/java/utils/NumericUtils.kt b/app/src/main/java/utils/NumericUtils.kt
index 8d12c35..e9f130b 100644
--- a/app/src/main/java/utils/NumericUtils.kt
+++ b/app/src/main/java/utils/NumericUtils.kt
@@ -7,6 +7,7 @@ import android.os.Build
 import android.util.Log
 import it.danieleverducci.lunatracker.R
 import it.danieleverducci.lunatracker.entities.LunaEvent
+import utils.DateUtils.Companion.formatTimeDuration
 import java.text.NumberFormat
 
 class NumericUtils (val context: Context) {
@@ -76,6 +77,7 @@ class NumericUtils (val context: Context) {
                         return ""
                     }
                 }
+                LunaEvent.TYPE_SLEEP -> formatTimeDuration(context, event.quantity.toLong())
                 else ->
                     event.quantity
             })
@@ -90,6 +92,11 @@ class NumericUtils (val context: Context) {
                     else -> ""
                 }
             )
+        } else {
+            formatted.append(when (event.type) {
+                LunaEvent.TYPE_SLEEP -> "💤" // baby is sleeping
+                else -> ""
+            })
         }
         return formatted.toString()
     }
diff --git a/app/src/main/res/layout/dialog_edit_duration.xml b/app/src/main/res/layout/dialog_edit_duration.xml
new file mode 100644
index 0000000..7ca379d
--- /dev/null
+++ b/app/src/main/res/layout/dialog_edit_duration.xml
@@ -0,0 +1,69 @@
+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout
+    xmlns:android="http://schemas.android.com/apk/res/android"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:layout_gravity="center"
+    android:gravity="center"
+    android:orientation="vertical">
+
+    <TextView
+        android:id="@+id/dialog_date_duration"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:textSize="20sp"
+        android:text="💤"/>
+
+    <LinearLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content"
+        android:gravity="center"
+        android:layout_marginTop="20dp"
+        android:layout_marginHorizontal="10dp"
+        android:orientation="horizontal">
+
+        <Button
+            android:id="@+id/dialog_date_duration_minus15"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="-15"/>
+
+        <Button
+            android:id="@+id/dialog_date_duration_minus5"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="-5"/>
+
+        <Button
+            android:id="@+id/dialog_date_duration_now"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="@string/now"/>
+
+        <Button
+            android:id="@+id/dialog_date_duration_plus5"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="+5"/>
+
+        <Button
+            android:id="@+id/dialog_date_duration_plus15"
+            android:layout_width="wrap_content"
+            android:layout_height="wrap_content"
+            android:layout_weight="1"
+            android:text="+15"/>
+
+    </LinearLayout>
+
+    <TextView
+        android:id="@+id/dialog_date_picker"
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:layout_gravity="center"
+        android:layout_marginTop="20dp"/>
+
+</LinearLayout>
diff --git a/app/src/main/res/layout/more_events_popup.xml b/app/src/main/res/layout/more_events_popup.xml
index b1dfbea..ef0cdf7 100644
--- a/app/src/main/res/layout/more_events_popup.xml
+++ b/app/src/main/res/layout/more_events_popup.xml
@@ -49,6 +49,16 @@
                 style="@style/OverflowMenuText"
                 android:text="@string/overflow_event_puke"/>
 
+            <TextView
+                android:id="@+id/button_sleep"
+                android:layout_width="match_parent"
+                android:layout_height="match_parent"
+                android:layout_marginTop="10dp"
+                android:padding="10dp"
+                android:background="@drawable/dropdown_list_item_background"
+                style="@style/OverflowMenuText"
+                android:text="@string/overflow_event_sleep"/>
+
             <TextView
                 android:id="@+id/button_colic"
                 android:layout_width="match_parent"
diff --git a/app/src/main/res/values/strings.xml b/app/src/main/res/values/strings.xml
index 487a06c..88ebd46 100644
--- a/app/src/main/res/values/strings.xml
+++ b/app/src/main/res/values/strings.xml
@@ -18,6 +18,7 @@
     <string name="event_colic_type" translatable="false">💨</string>
     <string name="event_puke_type" translatable="false">🤮</string>
     <string name="event_bath_type" translatable="false">🛁</string>
+    <string name="event_sleep_type" translatable="false">💤</string>
     <string name="event_unknown_type" translatable="false">\?</string>
 
     <string name="event_bottle_desc">Baby bottle</string>
@@ -35,6 +36,7 @@
     <string name="event_colic_desc">Gaseous colic</string>
     <string name="event_puke_desc">Puke</string>
     <string name="event_bath_desc">Bath</string>
+    <string name="event_sleep_desc">Sleep</string>
     <string name="event_unknown_desc"></string>
 
     <string name="overflow_event_weight">⚖️ Weight</string>
@@ -44,12 +46,14 @@
     <string name="overflow_event_temperature">🌡️ Temperature</string>
     <string name="overflow_event_colic">💨 Gaseous colic</string>
     <string name="overflow_event_puke">🤮 Puke</string>
+    <string name="overflow_event_sleep">💤 Sleep</string>
     <string name="overflow_event_bath">🛁 Bath</string>
 
     <string name="toast_event_added">Event logged</string>
     <string name="toast_logbook_saved">Logbook saved</string>
     <string name="toast_event_add_error">Unable to log the event</string>
     <string name="toast_integer_error">Invalid value. Insert an integer.</string>
+    <string name="toast_date_error">Invalid date.</string>
 
     <string name="now">now</string>
     <string name="second_ago">sec</string>
@@ -112,6 +116,7 @@
     <string name="log_temperature_dialog_description">Select the temperature:</string>
     <string name="log_unknown_dialog_description"></string>
     <string name="log_weight_dialog_description">Insert the weight:</string>
+    <string name="log_sleep_dialog_description">Set sleep duration:</string>
 
     <string name="measurement_unit_liquid_base_metric" translatable="false">ml</string>
     <string name="measurement_unit_weight_base_metric" translatable="false">g</string>