diff --git a/src/file/filecontentindexer.h b/src/file/filecontentindexer.h
--- a/src/file/filecontentindexer.h
+++ b/src/file/filecontentindexer.h
@@ -63,7 +63,7 @@
     Q_SCRIPTABLE void finishedIndexingFile(const QString& filePath);
 
     void done();
-    void newBatchTime(uint time);
+    void newBatchTime(uint time, uint batchSize);
 
 private Q_SLOTS:
     void monitorClosed(const QString& service);
diff --git a/src/file/filecontentindexer.cpp b/src/file/filecontentindexer.cpp
--- a/src/file/filecontentindexer.cpp
+++ b/src/file/filecontentindexer.cpp
@@ -81,26 +81,29 @@
 
         process.index(idList);
         loop.exec();
+        batchSize = idList.size();
 
-        // QDbus requires us to be in object creation thread (thread affinity)
-        // This signal is not even exported, and yet QDbus complains. QDbus bug?
-        QMetaObject::invokeMethod(this, "newBatchTime", Qt::QueuedConnection, Q_ARG(uint, timer.elapsed()));
 #if QT_VERSION < QT_VERSION_CHECK(5, 14, 0)
         if (hadErrors && !m_stop.load()) {
 #else
         if (hadErrors && !m_stop.loadRelaxed()) {
 #endif
-            if (idList.size() == 1) {
+            if (batchSize == 1) {
                 auto failedId = idList.first();
                 m_provider->markFailed(failedId);
                 batchSize = m_batchSize;
             } else {
-                batchSize = idList.size() / 2;
+                batchSize /= 2;
             }
             process.start();
+        } else {
+            auto elapsed = timer.elapsed();
+            QMetaObject::invokeMethod(this,
+                [this, elapsed, batchSize] { newBatchTime(elapsed, batchSize); },
+                Qt::QueuedConnection);
         }
     }
-    QMetaObject::invokeMethod(this, "done", Qt::QueuedConnection);
+    QMetaObject::invokeMethod(this, &FileContentIndexer::done, Qt::QueuedConnection);
 }
 
 void FileContentIndexer::slotStartedIndexingFile(const QString& filePath)
diff --git a/src/file/fileindexscheduler.cpp b/src/file/fileindexscheduler.cpp
--- a/src/file/fileindexscheduler.cpp
+++ b/src/file/fileindexscheduler.cpp
@@ -44,7 +44,7 @@
     , m_provider(db)
     , m_contentIndexer(nullptr)
     , m_indexerState(Startup)
-    , m_timeEstimator(config, this)
+    , m_timeEstimator(this)
     , m_checkUnindexedFiles(false)
     , m_checkStaleIndexEntries(false)
     , m_isGoingIdle(false)
diff --git a/src/file/timeestimator.h b/src/file/timeestimator.h
--- a/src/file/timeestimator.h
+++ b/src/file/timeestimator.h
@@ -40,20 +40,17 @@
 {
     Q_OBJECT
 public:
-    explicit TimeEstimator(FileIndexerConfig* config, QObject* parent = nullptr);
+    explicit TimeEstimator(QObject* parent = nullptr);
     uint calculateTimeLeft(int filesLeft);
 
 public Q_SLOTS:
-    void handleNewBatchTime(uint time);
+    void handleNewBatchTime(uint time, uint batchSize);
 
 private:
-    uint m_batchTimeBuffer[BUFFER_SIZE];
+    float m_batchTimeBuffer[BUFFER_SIZE];
 
     int m_bufferIndex;
     bool m_estimateReady;
-
-    FileIndexerConfig* m_config;
-    uint m_batchSize;
 };
 
 }
diff --git a/src/file/timeestimator.cpp b/src/file/timeestimator.cpp
--- a/src/file/timeestimator.cpp
+++ b/src/file/timeestimator.cpp
@@ -27,12 +27,10 @@
 
 using namespace Baloo;
 
-TimeEstimator::TimeEstimator(FileIndexerConfig *config, QObject* parent)
+TimeEstimator::TimeEstimator(QObject* parent)
     : QObject(parent)
     , m_bufferIndex(0)
     , m_estimateReady(false)
-    , m_config(config)
-    , m_batchSize(m_config->maxUncomittedFiles())
 {
 
 }
@@ -43,7 +41,6 @@
         return 0;
     }
 
-    //TODO: We should probably make the batch size a global macro
     float totalTime = 0;
     float totalWeight = 0;
 
@@ -57,20 +54,19 @@
     }
 
     float weightedAverage = totalTime / totalWeight;
-    float batchesLeft = (float)filesLeft / (float)m_batchSize;
 
-    return weightedAverage * batchesLeft;
+    return weightedAverage * filesLeft;
 }
 
-void TimeEstimator::handleNewBatchTime(uint time)
+void TimeEstimator::handleNewBatchTime(uint time, uint batchSize)
 {
     // add the current batch time in place of the oldest batch time
-    m_batchTimeBuffer[m_bufferIndex] = time;
+    m_batchTimeBuffer[m_bufferIndex] = (float)time / batchSize;
 
-    if (!m_estimateReady && m_bufferIndex == BUFFER_SIZE - 1) {
+    m_bufferIndex = (m_bufferIndex + 1) % BUFFER_SIZE;
+
+    if (!m_estimateReady && m_bufferIndex == 0) {
         // Buffer has been filled once. We are ready to estimate
         m_estimateReady = true;
     }
-
-    m_bufferIndex = (m_bufferIndex + 1) % BUFFER_SIZE;
 }