diff --git a/app/src/main/java/com/kabouzeid/gramophone/helper/StopWatch.java b/app/src/main/java/com/kabouzeid/gramophone/helper/StopWatch.java
index d65f9075..581d8fc2 100644
--- a/app/src/main/java/com/kabouzeid/gramophone/helper/StopWatch.java
+++ b/app/src/main/java/com/kabouzeid/gramophone/helper/StopWatch.java
@@ -1,5 +1,7 @@
 package com.kabouzeid.gramophone.helper;
 
+import java.util.Locale;
+
 /**
  * Simple thread safe stop watch.
  *
@@ -77,6 +79,6 @@ public class StopWatch {
 
     @Override
     public String toString() {
-        return String.format("%d millis", getElapsedTime());
+        return String.format(Locale.getDefault(), "%d millis", getElapsedTime());
     }
 }
diff --git a/app/src/main/java/com/kabouzeid/gramophone/lastfm/rest/LastFMRestClient.java b/app/src/main/java/com/kabouzeid/gramophone/lastfm/rest/LastFMRestClient.java
index d074023f..76b17c86 100644
--- a/app/src/main/java/com/kabouzeid/gramophone/lastfm/rest/LastFMRestClient.java
+++ b/app/src/main/java/com/kabouzeid/gramophone/lastfm/rest/LastFMRestClient.java
@@ -7,6 +7,7 @@ import android.support.annotation.Nullable;
 import com.kabouzeid.gramophone.lastfm.rest.service.LastFMService;
 
 import java.io.File;
+import java.util.Locale;
 
 import okhttp3.Cache;
 import okhttp3.Call;
@@ -54,7 +55,7 @@ public class LastFMRestClient {
     public static Interceptor createCacheControlInterceptor() {
         return chain -> {
             Request modifiedRequest = chain.request().newBuilder()
-                    .addHeader("Cache-Control", String.format("max-age=%d, max-stale=%d", 31536000, 31536000))
+                    .addHeader("Cache-Control", String.format(Locale.getDefault(), "max-age=%d, max-stale=%d", 31536000, 31536000))
                     .build();
             return chain.proceed(modifiedRequest);
         };
diff --git a/app/src/main/java/com/kabouzeid/gramophone/util/MusicUtil.java b/app/src/main/java/com/kabouzeid/gramophone/util/MusicUtil.java
index 97c46880..bbebbbec 100644
--- a/app/src/main/java/com/kabouzeid/gramophone/util/MusicUtil.java
+++ b/app/src/main/java/com/kabouzeid/gramophone/util/MusicUtil.java
@@ -35,6 +35,7 @@ import java.io.File;
 import java.io.IOException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.Locale;
 import java.util.regex.Pattern;
 
 /**
@@ -156,11 +157,11 @@ public class MusicUtil {
         long minutes = (songDurationMillis / 1000) / 60;
         long seconds = (songDurationMillis / 1000) % 60;
         if (minutes < 60) {
-            return String.format("%01d:%02d", minutes, seconds);
+            return String.format(Locale.getDefault(), "%01d:%02d", minutes, seconds);
         } else {
             long hours = minutes / 60;
             minutes = minutes % 60;
-            return String.format("%d:%02d:%02d", hours, minutes, seconds);
+            return String.format(Locale.getDefault(), "%d:%02d:%02d", hours, minutes, seconds);
         }
     }