Index: src/ExportManager.cpp
===================================================================
--- src/ExportManager.cpp
+++ src/ExportManager.cpp
@@ -175,6 +175,24 @@
 
     QString title;
 
+    SpectacleConfig *cfgManager = SpectacleConfig::instance();
+    QString sequentialFileNumber = cfgManager->nextSequentialFileNumber();
+    int paddedNumLength;
+    QRegularExpression seqRE;
+    seqRE.setPattern(QLatin1String("%\\d*d"));
+    QRegularExpressionMatch match;
+    if (baseName.indexOf(seqRE, 0, &match) > -1) {
+        paddedNumLength = match.captured().mid(1, match.captured().length() - 2).toInt();
+   } else {
+        paddedNumLength = 0;
+    }
+    if (sequentialFileNumber.toInt() >= 999999) {
+        cfgManager->setNextSequentialFileNumber(QString::number(1));    
+    } else {
+        cfgManager->setNextSequentialFileNumber(QString::number(sequentialFileNumber.toInt() + 1));    
+    }
+    
+ 
     if (mGrabMode == ImageGrabber::GrabMode::ActiveWindow ||
         mGrabMode == ImageGrabber::GrabMode::TransientWithParent ||
         mGrabMode == ImageGrabber::GrabMode::WindowUnderCursor) {
@@ -194,7 +212,9 @@
                              .replace(QLatin1String("%H"), timestamp.toString(QStringLiteral("hh")))
                              .replace(QLatin1String("%m"), timestamp.toString(QStringLiteral("mm")))
                              .replace(QLatin1String("%S"), timestamp.toString(QStringLiteral("ss")))
-                             .replace(QLatin1String("%T"), title);
+                             .replace(QLatin1String("%T"), title)
+                             .replace(seqRE, sequentialFileNumber.rightJustified(paddedNumLength, QLatin1Char('0'), false));
+ 
 
     // Remove leading and trailing '/'
     while (result.startsWith(QLatin1Char('/'))) {
Index: src/Gui/SettingsDialog/SaveOptionsPage.h
===================================================================
--- src/Gui/SettingsDialog/SaveOptionsPage.h
+++ src/Gui/SettingsDialog/SaveOptionsPage.h
@@ -52,6 +52,8 @@
     KUrlRequester    *mUrlRequester;
     QComboBox        *mSaveImageFormat;
     QCheckBox        *mCopyPathToClipboard;
+    QLineEdit        *mNextSequentialNumber;
+    QCheckBox        *mRestartSequentialNumberingOnRelaunch;
 
 };
 
Index: src/Gui/SettingsDialog/SaveOptionsPage.cpp
===================================================================
--- src/Gui/SettingsDialog/SaveOptionsPage.cpp
+++ src/Gui/SettingsDialog/SaveOptionsPage.cpp
@@ -28,14 +28,16 @@
 #include <QLabel>
 #include <QGroupBox>
 #include <QVBoxLayout>
+#include <QHBoxLayout>
 #include <QComboBox>
 #include <QImageWriter>
 #include <QCheckBox>
+#include <QIntValidator>
 
 SaveOptionsPage::SaveOptionsPage(QWidget *parent) :
     SettingsPage(parent)
 {
-    // set up the layout. start with the directory
+    // set up the layout. start with the directory groupbox
 
     QGroupBox *dirGroup = new QGroupBox(i18n("Default Save Location"), this);
     QVBoxLayout *dirLayout = new QVBoxLayout;
@@ -57,7 +59,7 @@
     connect(mCopyPathToClipboard, &QCheckBox::toggled, this, &SaveOptionsPage::markDirty);
     dirLayout->addWidget(mCopyPathToClipboard, 1);
 
-    // filename chooser text field
+    // filename chooser groupbox
 
     QGroupBox *fmtGroup = new QGroupBox(i18n("Default Save Filename"));
     QVBoxLayout *fmtLayout = new QVBoxLayout;
@@ -109,7 +111,8 @@
             "<b>%H</b>: Hour<br />"
             "<b>%m</b>: Minute<br />"
             "<b>%S</b>: Second<br />"
-            "<b>%T</b>: Window title"
+            "<b>%T</b>: Window title<br />"
+            "<b>%[N]d</b>: Sequential numbering (optionally include a number N to pad to that many digits)"
         "</blockquote>"
 
         "<p>To save to a sub-folder, use slashes to describe the desired path, e.g.:</p>"
@@ -125,6 +128,25 @@
     fmtHelpText->setTextFormat(Qt::RichText);
     fmtHelpText->setSizePolicy(QSizePolicy::MinimumExpanding, QSizePolicy::MinimumExpanding);
     fmtLayout->addWidget(fmtHelpText);
+    
+    // Sequential Numbering Settings
+    
+    QHBoxLayout *nextSequentialNumberLayout = new QHBoxLayout;
+    
+    nextSequentialNumberLayout->addWidget(new QLabel(i18n("Next sequential number:"), this));
+    mNextSequentialNumber = new QLineEdit;
+    QIntValidator *intValidator = new QIntValidator(1, 999999, this);
+    mNextSequentialNumber->setValidator(intValidator);
+    connect(mNextSequentialNumber, &QLineEdit::textEdited, this, &SaveOptionsPage::markDirty);
+    
+    mRestartSequentialNumberingOnRelaunch = new QCheckBox(i18n("Restart numbering with relaunch"), this);
+    connect(mRestartSequentialNumberingOnRelaunch, &QCheckBox::toggled, this, &SaveOptionsPage::markDirty);
+    dirLayout->addWidget(mRestartSequentialNumberingOnRelaunch, 1);
+    
+    nextSequentialNumberLayout->addWidget(mNextSequentialNumber);
+    nextSequentialNumberLayout->addWidget(mRestartSequentialNumberingOnRelaunch);
+
+    fmtLayout->addLayout(nextSequentialNumberLayout);
 
     // read in the data
 
@@ -158,6 +180,8 @@
     cfgManager->setAutoSaveFilenameFormat(mSaveNameFormat->text());
     cfgManager->setSaveImageFormat(mSaveImageFormat->currentText().toLower());
     cfgManager->setCopySaveLocationToClipboard(mCopyPathToClipboard->checkState() == Qt::Checked);
+    cfgManager->setNextSequentialFileNumber(mNextSequentialNumber->text());
+    cfgManager->setRestartSequentialNumberingOnRelaunch(mRestartSequentialNumberingOnRelaunch->checkState() == Qt::Checked);
 
     // done
 
@@ -175,6 +199,8 @@
     mSaveNameFormat->setText(cfgManager->autoSaveFilenameFormat());
     mUrlRequester->setUrl(QUrl::fromUserInput(cfgManager->autoSaveLocation()));
     mCopyPathToClipboard->setChecked(cfgManager->copySaveLocationToClipboard());
+    mNextSequentialNumber->setText(cfgManager->nextSequentialFileNumber());
+    mRestartSequentialNumberingOnRelaunch->setChecked(cfgManager->restartSequentialNumberingOnRelaunch());
 
     // read in the save image format and calculate its index
 
Index: src/SpectacleConfig.h
===================================================================
--- src/SpectacleConfig.h
+++ src/SpectacleConfig.h
@@ -108,6 +108,12 @@
     QString saveImageFormat() const;
     void setSaveImageFormat(const QString &saveFmt);
 
+    QString nextSequentialFileNumber() const;
+    void setNextSequentialFileNumber(QString num);
+    
+    bool restartSequentialNumberingOnRelaunch() const;
+    void setRestartSequentialNumberingOnRelaunch(bool enabled);
+
     private:
 
     KSharedConfigPtr mConfig;
Index: src/SpectacleConfig.cpp
===================================================================
--- src/SpectacleConfig.cpp
+++ src/SpectacleConfig.cpp
@@ -277,3 +277,29 @@
     mGeneralConfig.writeEntry(QStringLiteral("default-save-image-format"), saveFmt);
     mGeneralConfig.sync();
 }
+
+// next sequential file number
+
+QString SpectacleConfig::nextSequentialFileNumber() const
+{
+    return mGeneralConfig.readEntry(QStringLiteral("next-sequential-file-number"));
+}
+
+void SpectacleConfig::setNextSequentialFileNumber(QString nextNum)
+{
+    mGeneralConfig.writeEntry(QStringLiteral("next-sequential-file-number"), nextNum);
+}
+
+// restart sequential numbering on restart
+
+bool SpectacleConfig::restartSequentialNumberingOnRelaunch() const
+{
+    return mGeneralConfig.readEntry(QStringLiteral("restartSequentialNumberingOnRestart"), false);
+}
+
+void SpectacleConfig::setRestartSequentialNumberingOnRelaunch(bool enabled)
+{
+    mGeneralConfig.writeEntry(QStringLiteral("restartSequentialNumberingOnRestart"), enabled);
+    mGeneralConfig.sync();
+}
+
Index: src/SpectacleCore.cpp
===================================================================
--- src/SpectacleCore.cpp
+++ src/SpectacleCore.cpp
@@ -18,6 +18,7 @@
  */
 
 #include "SpectacleCore.h"
+#include "SpectacleConfig.h"
 
 #include "Config.h"
 #include "PlatformBackends/DummyImageGrabber.h"
@@ -309,5 +310,11 @@
 
         isGuiInited = true;
         QMetaObject::invokeMethod(mImageGrabber, "doImageGrab", Qt::QueuedConnection);
+
+        SpectacleConfig *cfgManager = SpectacleConfig::instance();
+        if (cfgManager->restartSequentialNumberingOnRelaunch()) {
+            cfgManager->setNextSequentialFileNumber(QStringLiteral("1"));
+        }
+
     }
 }