diff --git a/CMakeLists.txt b/CMakeLists.txt
index 81731f7be..1543bd119 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -6,7 +6,7 @@ if (CMAKE_VERSION GREATER_EQUAL "3.3")
   cmake_policy(SET CMP0167 NEW)
 endif ()  
 
-project(musrfit VERSION 1.11.0 LANGUAGES C CXX)
+project(musrfit VERSION 1.11.1 LANGUAGES C CXX)
 
 set(CMAKE_CXX_STANDARD 17)
 set(CMAKE_CXX_STANDARD_REQUIRED ON)
diff --git a/ChangeLog b/ChangeLog
index e6626faa4..0009ab1ae 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -12,6 +12,12 @@ or
 
 https://bitbucket.org/muonspin/musrfit
 
+Release of V1.11.1, 2026/06/07
+==============================
+
+allow from musredit (via preferences) to select the number of threads to be used
+for fitting.
+
 Release of V1.11.0, 2026/05/28
 ==============================
 
diff --git a/src/musredit_qt5/musredit/PAdmin.cpp b/src/musredit_qt5/musredit/PAdmin.cpp
index 649f9c55d..598e51fc6 100644
--- a/src/musredit_qt5/musredit/PAdmin.cpp
+++ b/src/musredit_qt5/musredit/PAdmin.cpp
@@ -168,6 +168,8 @@ bool PAdminXMLParser::startElement()
     fKeyWord = eEstimateN0;
   } else if (qName == "yaml_out") {
     fKeyWord = eYamlOut;
+  } else if (qName == "use_no_of_threads") {
+    fKeyWord = eNoOfTreadsToBeUsed;
   } else if (qName == "chisq_per_run_block") {
     fKeyWord = eChisqPreRunBlock;
   } else if (qName == "path_file_name") {
@@ -420,6 +422,11 @@ bool PAdminXMLParser::characters()
       fAdmin->fMsr2DataParam.perRunBlockChisq = flag;
       fAdmin->setChisqPerRunBlockFlag(flag);
       break;
+    case eNoOfTreadsToBeUsed:
+      ival = QString(str.toLatin1()).trimmed().toInt(&ok);
+      if (ok)
+        fAdmin->setNoOfThreadsToBeUsed(ival);
+      break;
     case eRecentFile:
       fAdmin->addRecentFile(QString(str.toLatin1()).trimmed());
       break;
@@ -993,6 +1000,9 @@ int PAdmin::savePrefs(QString pref_fln)
         else
           data[i] = "    <yaml_out>n</yaml_out>";
       }
+      if (data[i].contains("<use_no_of_threads>") && data[i].contains("</use_no_of_threads>")) {
+        data[i] = "    <use_no_of_threads>" + QString("%1").arg(fNoOfThreadsToBeUsed) + "</use_no_of_threads>";
+      }
       if (data[i].contains("<musrview_show_fourier>") && data[i].contains("</musrview_show_fourier>")) {
         if (fMusrviewShowFourier)
           data[i] = "    <musrview_show_fourier>y</musrview_show_fourier>";
diff --git a/src/musredit_qt5/musredit/PAdmin.h b/src/musredit_qt5/musredit/PAdmin.h
index d1bf5e5c2..929ce264f 100644
--- a/src/musredit_qt5/musredit/PAdmin.h
+++ b/src/musredit_qt5/musredit/PAdmin.h
@@ -70,7 +70,7 @@ class PAdminXMLParser
 
   private:
     enum EAdminKeyWords {eEmpty, eTimeout, eKeepMinuit2Output, eDumpAscii, eDumpRoot,
-                         eTitleFromDataFile, eChisqPreRunBlock, eEstimateN0, eYamlOut,
+                         eTitleFromDataFile, eChisqPreRunBlock, eEstimateN0, eYamlOut, eNoOfTreadsToBeUsed,
                          eMusrviewShowFourier, eMusrviewShowAvg, eMusrviewShowOneToOne, eEnableMusrT0,
                          eDarkThemeIconsMenu, eDarkThemeIconsToolbar, eIgnoreThemeAutoDetection, eEditW, eEditH,
                          eFontName, eFontSize, eExecPath, eDefaultSavePath,
@@ -128,6 +128,7 @@ class PAdmin : public QObject
     bool    getDumpRootFlag() { return fDumpRoot; }
     bool    getEstimateN0Flag() { return fEstimateN0; }
     bool    getYamlOutFlag() { return fYamlOut; }
+    int     getNoOfThreadsToBeUsed() { return fNoOfThreadsToBeUsed; }
     bool    getChisqPerRunBlockFlag() { return fChisqPreRunBlock; }
     bool    getIgnoreThemeAutoDetection() { return fIgnoreThemeAutoDetection; }
     bool    getDarkThemeIconsMenuFlag() { return fDarkThemeIconsMenu; }
@@ -158,6 +159,7 @@ class PAdmin : public QObject
     void setDumpRootFlag(const bool flag) { fDumpRoot = flag; }
     void setEstimateN0Flag(const bool flag) { fEstimateN0 = flag; }
     void setYamlOutFlag(const bool flag) { fYamlOut = flag; }
+    void setNoOfThreadsToBeUsed(const int num) { fNoOfThreadsToBeUsed = num; }
     void setChisqPerRunBlockFlag(const bool flag) { fChisqPreRunBlock = flag; }
     void setIgnoreThemeAutoDetection(const bool flag) { fIgnoreThemeAutoDetection = flag; }
     void setDarkThemeIconsMenuFlag(const bool flag) { fDarkThemeIconsMenu = flag; }
@@ -209,6 +211,7 @@ class PAdmin : public QObject
     bool fChisqPreRunBlock{false};     ///< flag indicating if musrfit shall write 'per run block' chisq to the msr-file (default: no).
     bool fEstimateN0{true};            ///< flag indicating if musrfit shall estimate N0 for single histogram fits (default: yes).
     bool fYamlOut{false};              ///< flag indicating if the MINUIT2.OUTPUT file should also be written as <msr-file>.yaml output. (default: no).
+    int  fNoOfThreadsToBeUsed{1};      ///< number of threads to be used
     bool fEnableMusrT0{true};          ///< flag indicating if musrT0 shall be enabled at startup from within musredit (default: yes).
     bool fIgnoreThemeAutoDetection{false}; ///< flag indicating that the theme autodetection shall be ignored. (default: no)
     bool fDarkThemeIconsMenu{false};   ///< flag indicating if dark theme icons shall be used in the menu (default: no)
diff --git a/src/musredit_qt5/musredit/PPrefsDialog.cpp b/src/musredit_qt5/musredit/PPrefsDialog.cpp
index d239b8d0e..c8dcf5d60 100644
--- a/src/musredit_qt5/musredit/PPrefsDialog.cpp
+++ b/src/musredit_qt5/musredit/PPrefsDialog.cpp
@@ -28,6 +28,7 @@
  ***************************************************************************/
 
 #include <memory>
+#include <unistd.h> // for # of threads
 
 #include "PChangeDefaultPathsDialog.h"
 #include "PPrefsDialog.h"
@@ -90,6 +91,15 @@ PPrefsDialog::PPrefsDialog(PAdmin *admin) : fAdmin(admin)
   fTimeout_lineEdit->setText(QString("%1").arg(fAdmin->getTimeout()));
   fTimeout_lineEdit->setValidator(new QIntValidator(fTimeout_lineEdit));
 
+  // get number of threads info from the systems
+  long nprocs = sysconf(_SC_NPROCESSORS_ONLN);
+  if (fAdmin->getNoOfThreadsToBeUsed() > nprocs)
+      fAdmin->setNoOfThreadsToBeUsed(nprocs);
+  for (auto i=0; i<nprocs; i++)
+      fNumberOfThreads_comboBox->addItem(QString("%1").arg(i+1));
+  fNumberOfThreads_comboBox->setCurrentIndex(fAdmin->getNoOfThreadsToBeUsed()-1);
+  QObject::connect(fNumberOfThreads_comboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(numberOfThreadsChanged(int)));
+
   QObject::connect(fDefaultPath_pushButton, SIGNAL(clicked()), this, SLOT(handleDefaultPaths()));
 }
 
@@ -145,6 +155,17 @@ void PPrefsDialog::handleDefaultPaths()
   }
 }
 
+//----------------------------------------------------------------------------------------------------
+/**
+ * @brief Slot: keeps the number of threads to be used for fitting.
+ *
+ * @param idx index of the comboBox
+ */
+void PPrefsDialog::numberOfThreadsChanged(int idx)
+{
+    fAdmin->setNoOfThreadsToBeUsed(idx+1);
+}
+
 //----------------------------------------------------------------------------------------------------
 // END
 //----------------------------------------------------------------------------------------------------
diff --git a/src/musredit_qt5/musredit/PPrefsDialog.h b/src/musredit_qt5/musredit/PPrefsDialog.h
index 8e911df12..7a282d59f 100644
--- a/src/musredit_qt5/musredit/PPrefsDialog.h
+++ b/src/musredit_qt5/musredit/PPrefsDialog.h
@@ -66,6 +66,7 @@ class PPrefsDialog : public QDialog, private Ui::PPrefsDialog
     void dumpAscii();
     void dumpRoot();
     void handleDefaultPaths();
+    void numberOfThreadsChanged(int idx);
 
   private:
     PAdmin *fAdmin;
diff --git a/src/musredit_qt5/musredit/PTextEdit.cpp b/src/musredit_qt5/musredit/PTextEdit.cpp
index 2c9b563c2..391892dec 100644
--- a/src/musredit_qt5/musredit/PTextEdit.cpp
+++ b/src/musredit_qt5/musredit/PTextEdit.cpp
@@ -2162,6 +2162,11 @@ void PTextEdit::musrFit()
     cmd.append("--yaml");
   }
 
+  // check how many threads to be used
+  cmd.append("--use-no-of-threads");
+  QString noThreads = QString("%1").arg(fAdmin->getNoOfThreadsToBeUsed());
+  cmd.append(noThreads);
+
   // check per-run-block-chisq flag
   if (fAdmin->getChisqPerRunBlockFlag()) {
     cmd.append("--per-run-block-chisq");
diff --git a/src/musredit_qt5/musredit/musredit_startup.xml.in b/src/musredit_qt5/musredit/musredit_startup.xml.in
index 35cab9590..6e2fe2f9e 100644
--- a/src/musredit_qt5/musredit/musredit_startup.xml.in
+++ b/src/musredit_qt5/musredit/musredit_startup.xml.in
@@ -15,6 +15,7 @@
     <chisq_per_run_block>n</chisq_per_run_block>
     <estimate_n0>y</estimate_n0>
     <yaml_out>n</yaml_out>
+    <use_no_of_threads>1024</use_no_of_threads>
     <musrview_show_fourier>n</musrview_show_fourier>
     <musrview_show_avg>n</musrview_show_avg>
     <musrview_show_one_to_one>n</musrview_show_one_to_one>
diff --git a/src/musredit_qt6/musredit/PAdmin.cpp b/src/musredit_qt6/musredit/PAdmin.cpp
index c6c003b99..c36fa398f 100644
--- a/src/musredit_qt6/musredit/PAdmin.cpp
+++ b/src/musredit_qt6/musredit/PAdmin.cpp
@@ -212,6 +212,8 @@ bool PAdminXMLParser::startElement()
     fKeyWord = eEstimateN0;
   } else if (qName == "yaml_out") {
     fKeyWord = eYamlOut;
+  } else if (qName == "use_no_of_threads") {
+    fKeyWord = eNoOfTreadsToBeUsed;
   } else if (qName == "chisq_per_run_block") {
     fKeyWord = eChisqPreRunBlock;
   } else if (qName == "path_file_name") {
@@ -469,6 +471,11 @@ bool PAdminXMLParser::characters()
       fAdmin->fMsr2DataParam.yamlOut = flag;
       fAdmin->setYamlOutFlag(flag);
       break;
+    case eNoOfTreadsToBeUsed:
+      ival = QString(str.toLatin1()).trimmed().toInt(&ok);
+      if (ok)
+        fAdmin->setNoOfThreadsToBeUsed(ival);
+      break;
     case eChisqPreRunBlock:
       if (str == "y")
         flag = true;
@@ -1134,6 +1141,9 @@ int PAdmin::savePrefs(QString pref_fln)
         else
           data[i] = "    <yaml_out>n</yaml_out>";
       }
+      if (data[i].contains("<use_no_of_threads>") && data[i].contains("</use_no_of_threads>")) {
+          data[i] = "    <use_no_of_threads>" + QString("%1").arg(fNoOfThreadsToBeUsed) + "</use_no_of_threads>";
+      }
       if (data[i].contains("<musrview_show_fourier>") && data[i].contains("</musrview_show_fourier>")) {
         if (fMusrviewShowFourier)
           data[i] = "    <musrview_show_fourier>y</musrview_show_fourier>";
diff --git a/src/musredit_qt6/musredit/PAdmin.h b/src/musredit_qt6/musredit/PAdmin.h
index d3bf0a106..250864a76 100644
--- a/src/musredit_qt6/musredit/PAdmin.h
+++ b/src/musredit_qt6/musredit/PAdmin.h
@@ -143,7 +143,7 @@ class PAdminXMLParser
      * The parser uses these to determine how to process element content.
      */
     enum EAdminKeyWords {eEmpty, eTimeout, eKeepMinuit2Output, eDumpAscii, eDumpRoot,
-                         eTitleFromDataFile, eChisqPreRunBlock, eEstimateN0, eYamlOut,
+                         eTitleFromDataFile, eChisqPreRunBlock, eEstimateN0, eYamlOut, eNoOfTreadsToBeUsed,
                          eMusrviewShowFourier, eMusrviewShowAvg, eMusrviewShowOneToOne, eEnableMusrT0,
                          eIgnoreThemeAutoDetection, eDarkThemeIconsMenu, eDarkThemeIconsToolbar, eEditW, eEditH,
                          eFontName, eFontSize, eExecPath, eDefaultSavePath,
@@ -225,6 +225,7 @@ class PAdmin : public QObject
     bool    getMusrviewShowOneToOneFlag() { return fMusrviewShowOneToOne; } ///< Check if one-to-one theory display is enabled.
     bool    getEnableMusrT0Flag() { return fEnableMusrT0; }               ///< Check if musrT0 is enabled.
     bool    getYamlOutFlag() { return fYamlOut; }                         ///< Check if YAML output is enabled.
+    int     getNoOfThreadsToBeUsed() { return fNoOfThreadsToBeUsed; }     ///< Get number of threads to be used
     bool    getKeepMinuit2OutputFlag() { return fKeepMinuit2Output; }     ///< Check if MINUIT2 output files are preserved.
     bool    getDumpAsciiFlag() { return fDumpAscii; }                     ///< Check if ASCII dump is enabled.
     bool    getDumpRootFlag() { return fDumpRoot; }                       ///< Check if ROOT dump is enabled.
@@ -264,6 +265,7 @@ class PAdmin : public QObject
     void setDumpRootFlag(const bool flag) { fDumpRoot = flag; }                    ///< Enable/disable ROOT dump.
     void setEstimateN0Flag(const bool flag) { fEstimateN0 = flag; }                ///< Enable/disable N0 estimation.
     void setYamlOutFlag(const bool flag) { fYamlOut = flag; }                      ///< Enable/disable YAML output.
+    void setNoOfThreadsToBeUsed(const int num) { fNoOfThreadsToBeUsed = num; }     ///< set number of threads to be used
     void setChisqPerRunBlockFlag(const bool flag) { fChisqPreRunBlock = flag; }    ///< Enable/disable per-run-block chi-square.
     void setIgnoreThemeAutoDetection(const bool flag) { fIgnoreThemeAutoDetection = flag; } ///< Enable/disable theme auto-detection.
     void setDarkThemeIconsMenuFlag(const bool flag) { fDarkThemeIconsMenu = flag; }   ///< Enable/disable dark theme menu icons.
@@ -356,6 +358,7 @@ class PAdmin : public QObject
     bool fChisqPreRunBlock{false};     ///< If true, write per-run-block chi-square values to msr-file.
     bool fEstimateN0{true};            ///< If true, estimate N0 parameter for single histogram fits.
     bool fYamlOut{false};              ///< If true, write MINUIT2 output additionally as \<msr-file\>.yaml.
+    int  fNoOfThreadsToBeUsed{1};      ///< number of threads to be used
     /** @} */
 
     /** @name MSR File Defaults
diff --git a/src/musredit_qt6/musredit/PPrefsDialog.cpp b/src/musredit_qt6/musredit/PPrefsDialog.cpp
index 3004c8267..33d53357a 100644
--- a/src/musredit_qt6/musredit/PPrefsDialog.cpp
+++ b/src/musredit_qt6/musredit/PPrefsDialog.cpp
@@ -45,6 +45,7 @@
  */
 
 #include <memory>
+#include <unistd.h> // for # of threads
 
 #include "PChangeDefaultPathsDialog.h"
 #include "PPrefsDialog.h"
@@ -164,6 +165,15 @@ PPrefsDialog::PPrefsDialog(PAdmin *admin) : fAdmin(admin)
   fTimeout_lineEdit->setText(QString("%1").arg(fAdmin->getTimeout()));
   fTimeout_lineEdit->setValidator(new QIntValidator(fTimeout_lineEdit));
 
+  // get number of threads info from the systems
+  long nprocs = sysconf(_SC_NPROCESSORS_ONLN);
+  if (fAdmin->getNoOfThreadsToBeUsed() > nprocs)
+    fAdmin->setNoOfThreadsToBeUsed(nprocs);
+  for (auto i=0; i<nprocs; i++)
+    fNumberOfThreads_comboBox->addItem(QString("%1").arg(i+1));
+  fNumberOfThreads_comboBox->setCurrentIndex(fAdmin->getNoOfThreadsToBeUsed()-1);
+  QObject::connect(fNumberOfThreads_comboBox, SIGNAL(currentIndexChanged(int)), this, SLOT(numberOfThreadsChanged(int)));
+
   QObject::connect(fDefaultPath_pushButton, SIGNAL(clicked()), this, SLOT(handleDefaultPaths()));
 }
 
@@ -340,6 +350,17 @@ void PPrefsDialog::handleDefaultPaths()
   }
 }
 
+//----------------------------------------------------------------------------------------------------
+/**
+ * @brief Slot: keeps the number of threads to be used for fitting.
+ *
+ * @param idx index of the comboBox
+ */
+void PPrefsDialog::numberOfThreadsChanged(int idx)
+{
+  fAdmin->setNoOfThreadsToBeUsed(idx+1);
+}
+
 //----------------------------------------------------------------------------------------------------
 // END
 //----------------------------------------------------------------------------------------------------
diff --git a/src/musredit_qt6/musredit/PPrefsDialog.h b/src/musredit_qt6/musredit/PPrefsDialog.h
index 1489e571f..d3c8670ae 100644
--- a/src/musredit_qt6/musredit/PPrefsDialog.h
+++ b/src/musredit_qt6/musredit/PPrefsDialog.h
@@ -318,6 +318,13 @@ class PPrefsDialog : public QDialog, private Ui::PPrefsDialog
      */
     void handleDefaultPaths();
 
+    /**
+     * @brief Slot: called when the current index of the number of threads to be used has changed
+     *
+     * @param idx index of the comboBox
+     */
+    void numberOfThreadsChanged(int idx);
+
   private:
     PAdmin *fAdmin; ///< Pointer to global administration object storing all preferences.
 };
diff --git a/src/musredit_qt6/musredit/PTextEdit.cpp b/src/musredit_qt6/musredit/PTextEdit.cpp
index 9e9f31aff..d1a1db9c0 100644
--- a/src/musredit_qt6/musredit/PTextEdit.cpp
+++ b/src/musredit_qt6/musredit/PTextEdit.cpp
@@ -2273,6 +2273,11 @@ void PTextEdit::musrFit()
     cmd.append("--yaml");
   }
 
+  // check how many threads to be used
+  cmd.append("--use-no-of-threads");
+  QString noThreads = QString("%1").arg(fAdmin->getNoOfThreadsToBeUsed());
+  cmd.append(noThreads);
+
   // check per-run-block-chisq flag
   if (fAdmin->getChisqPerRunBlockFlag()) {
     cmd.append("--per-run-block-chisq");
diff --git a/src/musredit_qt6/musredit/forms/PPrefsDialog.ui b/src/musredit_qt6/musredit/forms/PPrefsDialog.ui
index 3cacd6a8a..ef6d0eeed 100644
--- a/src/musredit_qt6/musredit/forms/PPrefsDialog.ui
+++ b/src/musredit_qt6/musredit/forms/PPrefsDialog.ui
@@ -3,7 +3,7 @@
  <class>PPrefsDialog</class>
  <widget class="QDialog" name="PPrefsDialog">
   <property name="windowModality">
-   <enum>Qt::WindowModal</enum>
+   <enum>Qt::WindowModality::WindowModal</enum>
   </property>
   <property name="geometry">
    <rect>
@@ -26,13 +26,13 @@
      <item>
       <widget class="QTabWidget" name="fTabWidget">
        <property name="currentIndex">
-        <number>0</number>
+        <number>1</number>
        </property>
        <widget class="QWidget" name="fGeneral_tab">
         <attribute name="title">
          <string>general</string>
         </attribute>
-        <widget class="QWidget" name="">
+        <widget class="QWidget" name="layoutWidget">
          <property name="geometry">
           <rect>
            <x>11</x>
@@ -57,7 +57,7 @@
             <item>
              <spacer name="horizontalSpacer_2">
               <property name="orientation">
-               <enum>Qt::Horizontal</enum>
+               <enum>Qt::Orientation::Horizontal</enum>
               </property>
               <property name="sizeHint" stdset="0">
                <size>
@@ -97,7 +97,7 @@
           <item>
            <spacer name="verticalSpacer">
             <property name="orientation">
-             <enum>Qt::Vertical</enum>
+             <enum>Qt::Orientation::Vertical</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -117,7 +117,7 @@
           <item>
            <spacer name="verticalSpacer_2">
             <property name="orientation">
-             <enum>Qt::Vertical</enum>
+             <enum>Qt::Orientation::Vertical</enum>
             </property>
             <property name="sizeHint" stdset="0">
              <size>
@@ -225,6 +225,28 @@
           <string>yaml out</string>
          </property>
         </widget>
+        <widget class="QWidget" name="">
+         <property name="geometry">
+          <rect>
+           <x>10</x>
+           <y>90</y>
+           <width>291</width>
+           <height>34</height>
+          </rect>
+         </property>
+         <layout class="QHBoxLayout" name="horizontalLayout_4">
+          <item>
+           <widget class="QComboBox" name="fNumberOfThreads_comboBox"/>
+          </item>
+          <item>
+           <widget class="QLabel" name="fNumberOfThreads_label">
+            <property name="text">
+             <string># threads to be used</string>
+            </property>
+           </widget>
+          </item>
+         </layout>
+        </widget>
        </widget>
        <widget class="QWidget" name="fMusrview_tab">
         <attribute name="title">
@@ -302,7 +324,7 @@
        <item>
         <spacer name="horizontalSpacer">
          <property name="orientation">
-          <enum>Qt::Horizontal</enum>
+          <enum>Qt::Orientation::Horizontal</enum>
          </property>
          <property name="sizeHint" stdset="0">
           <size>
diff --git a/src/musredit_qt6/musredit/musredit_startup.xml.in b/src/musredit_qt6/musredit/musredit_startup.xml.in
index 35cab9590..6e2fe2f9e 100644
--- a/src/musredit_qt6/musredit/musredit_startup.xml.in
+++ b/src/musredit_qt6/musredit/musredit_startup.xml.in
@@ -15,6 +15,7 @@
     <chisq_per_run_block>n</chisq_per_run_block>
     <estimate_n0>y</estimate_n0>
     <yaml_out>n</yaml_out>
+    <use_no_of_threads>1024</use_no_of_threads>
     <musrview_show_fourier>n</musrview_show_fourier>
     <musrview_show_avg>n</musrview_show_avg>
     <musrview_show_one_to_one>n</musrview_show_one_to_one>