diff --git a/res/values/strings.xml b/res/values/strings.xml
index bdcb97a711d324daeaf055355baed32989f357b5..9ad6749abfd3dd9e4e1888c6de217af70e1a8001 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -61,6 +61,8 @@
     <string name="dialog_prepare_zip_message">Preliminary update preparation</string>
     <string name="dialog_battery_low_title">Low battery</string>
     <string name="dialog_battery_low_message_pct">The battery level is too low, you need at least <xliff:g id="percent_discharging">%1$d</xliff:g>%% of the battery to continue, <xliff:g id="percent_charging">%2$d</xliff:g>%% if charging.</string>
+    <string name="dialog_free_space_low_title">Free up space</string>
+    <string name="dialog_free_space_low_message_pct">The update cannot be completed because there is insufficient free space; at least <xliff:g id="needed_free_space">%1$s</xliff:g> of free space is required. Please clear your internal storage before proceeding.</string>
 
     <string name="reboot">Reboot</string>
 
diff --git a/src/org/lineageos/updater/UpdatesActivity.java b/src/org/lineageos/updater/UpdatesActivity.java
index 6ae81edf431ab49749fa155294db8347cc26bc95..47d0b72a08f70d3876d061fcd20c8cdda1599692 100644
--- a/src/org/lineageos/updater/UpdatesActivity.java
+++ b/src/org/lineageos/updater/UpdatesActivity.java
@@ -21,9 +21,9 @@ import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
-import android.content.res.Configuration;
 import android.content.ServiceConnection;
 import android.content.SharedPreferences;
+import android.content.res.Configuration;
 import android.icu.text.DateFormat;
 import android.net.Uri;
 import android.os.Build;
@@ -37,13 +37,11 @@ import android.view.View;
 import android.view.animation.Animation;
 import android.view.animation.LinearInterpolator;
 import android.view.animation.RotateAnimation;
-import android.widget.Button;
 import android.widget.Spinner;
 import android.widget.Switch;
 import android.widget.TextView;
 
 import androidx.appcompat.app.AlertDialog;
-import androidx.appcompat.app.AppCompatDelegate;
 import androidx.appcompat.widget.Toolbar;
 import androidx.core.content.ContextCompat;
 import androidx.localbroadcastmanager.content.LocalBroadcastManager;
diff --git a/src/org/lineageos/updater/UpdatesListAdapter.java b/src/org/lineageos/updater/UpdatesListAdapter.java
index bcf3f779e199066fcd74ca0ff77e8f764b403ba4..82304df6b141e3f6dcb0c9596f38ea9be13fc777 100644
--- a/src/org/lineageos/updater/UpdatesListAdapter.java
+++ b/src/org/lineageos/updater/UpdatesListAdapter.java
@@ -50,7 +50,6 @@ import com.google.android.material.snackbar.Snackbar;
 
 import org.lineageos.updater.controller.UpdaterController;
 import org.lineageos.updater.controller.UpdaterService;
-import org.lineageos.updater.misc.BuildInfoUtils;
 import org.lineageos.updater.misc.Constants;
 import org.lineageos.updater.misc.PermissionsUtils;
 import org.lineageos.updater.misc.StringGenerator;
@@ -454,8 +453,8 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
     }
 
     private AlertDialog.Builder getInstallDialog(final String downloadId) {
+        Resources resources = mActivity.getResources();
         if (!isBatteryLevelOk()) {
-            Resources resources = mActivity.getResources();
             String message = resources.getString(R.string.dialog_battery_low_message_pct,
                     resources.getInteger(R.integer.battery_ok_percentage_discharging),
                     resources.getInteger(R.integer.battery_ok_percentage_charging));
@@ -498,6 +497,17 @@ public class UpdatesListAdapter extends RecyclerView.Adapter<UpdatesListAdapter.
             return null;
         }
 
+        long neededSpace = update.getFileSize() * 2;
+        final boolean hasFreeSpace = Utils.availableFreeSpace() >= neededSpace;
+        if (!hasFreeSpace) {
+            String spaceMessage = resources.getString(R.string.dialog_free_space_low_message_pct,
+                    Utils.getFileSize(neededSpace));
+            return new AlertDialog.Builder(mActivity)
+                    .setTitle(R.string.dialog_free_space_low_title)
+                    .setMessage(spaceMessage)
+                    .setPositiveButton(android.R.string.ok, null);
+        }
+
         return new AlertDialog.Builder(mActivity)
                 .setTitle(title)
                 .setMessage(message)
diff --git a/src/org/lineageos/updater/controller/UpdaterService.java b/src/org/lineageos/updater/controller/UpdaterService.java
index c2ee31f6d480a3c1fb69b3665f9d2561a3b475d3..21da556f75fc9090fb57a82a9ce56225e7f87c9d 100644
--- a/src/org/lineageos/updater/controller/UpdaterService.java
+++ b/src/org/lineageos/updater/controller/UpdaterService.java
@@ -37,7 +37,6 @@ import androidx.preference.PreferenceManager;
 import org.lineageos.updater.R;
 import org.lineageos.updater.UpdaterReceiver;
 import org.lineageos.updater.UpdatesActivity;
-import org.lineageos.updater.misc.BuildInfoUtils;
 import org.lineageos.updater.misc.Constants;
 import org.lineageos.updater.misc.StringGenerator;
 import org.lineageos.updater.misc.Utils;
diff --git a/src/org/lineageos/updater/download/HttpURLConnectionClient.java b/src/org/lineageos/updater/download/HttpURLConnectionClient.java
index 573a249239d14ded45ccac5c70976a893bd21f46..ecf62520db7294af34efb13320017b49d19a7eb8 100644
--- a/src/org/lineageos/updater/download/HttpURLConnectionClient.java
+++ b/src/org/lineageos/updater/download/HttpURLConnectionClient.java
@@ -17,9 +17,10 @@ package org.lineageos.updater.download;
 
 import android.os.SystemClock;
 import android.os.SystemProperties;
-
 import android.util.Log;
 
+import org.lineageos.updater.misc.Constants;
+
 import java.io.File;
 import java.io.FileOutputStream;
 import java.io.IOException;
@@ -34,8 +35,6 @@ import java.util.PriorityQueue;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
-import org.lineageos.updater.misc.Constants;
-
 public class HttpURLConnectionClient implements DownloadClient {
 
     private final static String TAG = "HttpURLConnectionClient";
diff --git a/src/org/lineageos/updater/misc/Utils.java b/src/org/lineageos/updater/misc/Utils.java
index 1574bc32f732eb14974fc499479ffa2c02664a5e..0ba3f46191e3b65393aca2081e7b9d7a282ebcad 100644
--- a/src/org/lineageos/updater/misc/Utils.java
+++ b/src/org/lineageos/updater/misc/Utils.java
@@ -28,6 +28,7 @@ import android.net.ConnectivityManager;
 import android.net.NetworkInfo;
 import android.net.Uri;
 import android.os.Environment;
+import android.os.StatFs;
 import android.os.SystemProperties;
 import android.os.storage.StorageManager;
 import android.util.Log;
@@ -49,15 +50,14 @@ import java.io.BufferedReader;
 import java.io.File;
 import java.io.FileReader;
 import java.io.IOException;
+import java.text.DecimalFormat;
 import java.util.ArrayList;
 import java.util.Enumeration;
-import java.util.HashSet;
 import java.util.List;
 import java.util.Locale;
-import java.util.Set;
+import java.util.regex.Pattern;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipFile;
-import java.util.regex.Pattern;
 
 
 public class Utils {
@@ -151,6 +151,20 @@ public class Utils {
         return new int[]{ major, minor };
     }
 
+    public static long availableFreeSpace() {
+        StatFs stats = new StatFs(Environment.getDataDirectory().getAbsolutePath());
+        return stats.getAvailableBlocksLong() * stats.getBlockSizeLong();
+    }
+
+    // https://stackoverflow.com/a/28527441
+    public static String getFileSize(long size) {
+        if (size <= 0)
+            return "0";
+        final String[] units = new String[] { "B", "KB", "MB", "GB", "TB" };
+        int digitGroups = (int) (Math.log10(size) / Math.log10(1024));
+        return new DecimalFormat("#,##0.#").format(size / Math.pow(1024, digitGroups)) + " " + units[digitGroups];
+    }
+
     public static boolean canInstall(UpdateBaseInfo update) {
         return (SystemProperties.getBoolean(Constants.PROP_UPDATER_ALLOW_DOWNGRADING, false) ||
                 update.getTimestamp() > SystemProperties.getLong(Constants.PROP_BUILD_DATE, 0));