diff --git a/TODO b/TODO
index e1f857cab..bf453e922 100644
--- a/TODO
+++ b/TODO
@@ -81,5 +81,6 @@ beta5->beta6 changelog:
 - BUGFIX: Prevent downloadFromUrl flooding
 - BUGFIX: Made finished list context menu more similar to the download list one
 - BUGFIX: Fixed Pause/Start action in lists context menus
+- BUGFIX: Improved ETA calculation
 - BUGFIX: Display the torrent that are being checked as 'checking' in seeding list
 - I18N: Removed no longer maintained Traditional chinese translation
\ No newline at end of file
diff --git a/src/bittorrent.cpp b/src/bittorrent.cpp
index 68e9e81fc..0d4e2856e 100644
--- a/src/bittorrent.cpp
+++ b/src/bittorrent.cpp
@@ -112,19 +112,22 @@ void bittorrent::updateETAs() {
     QTorrentHandle h = handles[i];
     if(h.is_valid()) {
       QString hash = h.hash();
-      QList<long> listEtas = ETAstats.value(hash, QList<long>());
+      QList<qlonglong> listEtas = ETAstats.value(hash, QList<qlonglong>());
       if(listEtas.size() == ETAS_MAX_VALUES) {
           listEtas.removeFirst();
       }
-      if(h.download_payload_rate() != 0) {
-        listEtas << (long)((h.total_size()-h.total_done())/(double)h.download_payload_rate());
+      if(h.download_payload_rate()) {
+        listEtas << (qlonglong)((h.total_size()-h.total_done())/(double)h.download_payload_rate());
         ETAstats[hash] = listEtas;
         long moy = 0;
         long val;
+        unsigned int nbETAs = listEtas.size();
+        Q_ASSERT(nbETAs);
         foreach(val, listEtas) {
-          moy += val;
+          moy += (qlonglong)((double)val/(double)nbETAs);
+          Q_ASSERT(moy >= 0);
         }
-        ETAs[hash] = (long) ((double)moy/(double)listEtas.size());
+        ETAs[hash] = moy;
       }
     }
   }
diff --git a/src/bittorrent.h b/src/bittorrent.h
index a31359dba..fea40c790 100644
--- a/src/bittorrent.h
+++ b/src/bittorrent.h
@@ -49,8 +49,8 @@ class bittorrent : public QObject{
     QString defaultSavePath;
     QStringList torrentsToPauseAfterChecking;
     QStringList reloadingTorrents;
-    QHash<QString, QList<long> > ETAstats;
-    QHash<QString, long> ETAs;
+    QHash<QString, QList<qlonglong> > ETAstats;
+    QHash<QString, qlonglong> ETAs;
     QHash<QString, QPair<size_type,size_type> > ratioData;
     QTimer *ETARefresher;
     QStringList fullAllocationModeList;
diff --git a/src/misc.h b/src/misc.h
index 00e5059a0..faf8c72ef 100644
--- a/src/misc.h
+++ b/src/misc.h
@@ -285,28 +285,36 @@ class misc : public QObject{
 
     // Take a number of seconds and return an user-friendly
     // time duration like "1d 2h 10m".
-    static QString userFriendlyDuration(const long int seconds) {
-      if(seconds < 0) {
+    static QString userFriendlyDuration(qlonglong seconds) {
+      if(seconds < 0 or seconds > 8640000) {
         return tr("Unknown");
       }
-      if(seconds < 60) {
-        return tr("< 1m", "< 1 minute");
+      int level = 0;
+      int days = int(seconds / 86400.);
+      if(!days)
+        level = 1;
+      else
+        seconds -= days * 86400;
+      int hours = int(seconds / 3600.);
+      if(!hours)
+        level = 2;
+      else
+        seconds -= hours * 3600;
+      int minutes = int(seconds / 60.0);
+      if(!minutes)
+        level = 3;
+      else
+        seconds -= minutes * 60;
+      switch(level){
+        case 3:
+          return tr("< 1m", "< 1 minute");
+        case 2:
+          return tr("%1m","e.g: 10minutes").arg(QString::QString::fromUtf8(misc::toString(minutes).c_str()));
+        case 1:
+          return tr("%1h%2m", "e.g: 3hours 5minutes").arg(QString::fromUtf8(misc::toString(hours).c_str())).arg(QString::fromUtf8(misc::toString(minutes).c_str()));
+        default:
+          return tr("%1d%2h%3m", "e.g: 2days 10hours 2minutes").arg(QString::fromUtf8(misc::toString(days).c_str())).arg(QString::fromUtf8(misc::toString(hours).c_str())).arg(QString::fromUtf8(misc::toString(minutes).c_str()));
       }
-      int minutes = seconds / 60;
-      if(minutes < 60) {
-        return tr("%1m","e.g: 10minutes").arg(QString::QString::fromUtf8(misc::toString(minutes).c_str()));
-      }
-      int hours = minutes / 60;
-      minutes = minutes - hours*60;
-      if(hours < 24) {
-        return tr("%1h%2m", "e.g: 3hours 5minutes").arg(QString::fromUtf8(misc::toString(hours).c_str())).arg(QString::fromUtf8(misc::toString(minutes).c_str()));
-      }
-      int days = hours / 24;
-      hours = hours - days * 24;
-      if(days < 100) {
-        return tr("%1d%2h%3m", "e.g: 2days 10hours 2minutes").arg(QString::fromUtf8(misc::toString(days).c_str())).arg(QString::fromUtf8(misc::toString(hours).c_str())).arg(QString::fromUtf8(misc::toString(minutes).c_str()));
-      }
-      return tr("Unknown");
     }
 };
 
diff --git a/src/src.pro b/src/src.pro
index 8689f4d81..f5f877f48 100644
--- a/src/src.pro
+++ b/src/src.pro
@@ -19,15 +19,15 @@ DEFINES += VERSION_BUGFIX=0
 contains(DEBUG_MODE, 1){
   CONFIG += debug
   CONFIG -= release
-  QMAKE_CXXFLAGS_RELEASE += -O1
-  QMAKE_CXXFLAGS_DEBUG += -O1
+  QMAKE_CXXFLAGS_RELEASE += -fwrapv -O1
+  QMAKE_CXXFLAGS_DEBUG += -fwrapv -O1
   message(Debug build!)
 }
 contains(DEBUG_MODE, 0){
   CONFIG -= debug
   CONFIG += release
-  QMAKE_CXXFLAGS_RELEASE += -O2
-  QMAKE_CXXFLAGS_DEBUG += -O2
+  QMAKE_CXXFLAGS_RELEASE += -fwrapv -O2
+  QMAKE_CXXFLAGS_DEBUG += -fwrapv -O2
   message(Release build!)
 }