diff --git a/cmake/qet_compilation_vars.cmake b/cmake/qet_compilation_vars.cmake
index c0daa3aca..6cd543f73 100644
--- a/cmake/qet_compilation_vars.cmake
+++ b/cmake/qet_compilation_vars.cmake
@@ -277,6 +277,8 @@ set(QET_SRC_FILES
   ${QET_DIR}/sources/autoNum/numerotationcontextcommands.h
   ${QET_DIR}/sources/autoNum/numerotationcontext.cpp
   ${QET_DIR}/sources/autoNum/numerotationcontext.h
+  ${QET_DIR}/sources/autoNum/renumberelementscommand.cpp
+  ${QET_DIR}/sources/autoNum/renumberelementscommand.h
   ${QET_DIR}/sources/autoNum/ui/autonumberingdockwidget.cpp
   ${QET_DIR}/sources/autoNum/ui/autonumberingdockwidget.h
   ${QET_DIR}/sources/autoNum/ui/autonumberingmanagementw.cpp
@@ -287,6 +289,8 @@ set(QET_SRC_FILES
   ${QET_DIR}/sources/autoNum/ui/formulaautonumberingw.h
   ${QET_DIR}/sources/autoNum/ui/numparteditorw.cpp
   ${QET_DIR}/sources/autoNum/ui/numparteditorw.h
+  ${QET_DIR}/sources/autoNum/ui/renumberelementsdialog.cpp
+  ${QET_DIR}/sources/autoNum/ui/renumberelementsdialog.h
   ${QET_DIR}/sources/autoNum/ui/selectautonumw.cpp
   ${QET_DIR}/sources/autoNum/ui/selectautonumw.h
 
diff --git a/sources/autoNum/renumberelementscommand.cpp b/sources/autoNum/renumberelementscommand.cpp
new file mode 100644
index 000000000..27f2c5912
--- /dev/null
+++ b/sources/autoNum/renumberelementscommand.cpp
@@ -0,0 +1,78 @@
+/*
+    Copyright 2006-2026 The QElectroTech Team
+    This file is part of QElectroTech.
+
+    QElectroTech is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    QElectroTech is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "renumberelementscommand.h"
+
+#include "../qetproject.h"
+#include "../qetgraphicsitem/element.h"
+
+RenumberElementsCommand::RenumberElementsCommand(
+        QETProject *project,
+        QVector<ElementChange> changes,
+        QHash<QString, NumerotationContext> old_ctx,
+        QHash<QString, NumerotationContext> new_ctx,
+        const QString &text)
+    : QUndoCommand(text)
+    , project_(project)
+    , changes_(std::move(changes))
+    , old_ctx_(std::move(old_ctx))
+    , new_ctx_(std::move(new_ctx))
+{
+}
+
+void RenumberElementsCommand::undo()
+{
+    apply(false);
+}
+
+void RenumberElementsCommand::redo()
+{
+    // QUndoStack calls redo() once immediately after push(); keep standard behaviour.
+    if (first_redo_) {
+        first_redo_ = false;
+    }
+    apply(true);
+}
+
+void RenumberElementsCommand::apply(bool use_new)
+{
+    if (!project_) return;
+
+    // Restore project contexts
+    const auto &ctx = use_new ? new_ctx_ : old_ctx_;
+    for (auto it = ctx.constBegin(); it != ctx.constEnd(); ++it) {
+        project_->addElementAutoNum(it.key(), it.value());
+    }
+
+    // Apply per-element changes
+    for (const ElementChange &c : changes_) {
+        if (!c.element) continue;
+
+        const bool frozen = use_new ? c.new_frozen : c.old_frozen;
+        const auto &infos = use_new ? c.new_infos : c.old_infos;
+        const auto &seq   = use_new ? c.new_seq   : c.old_seq;
+
+        // Temporarily unfreeze so that label/infos update correctly.
+        const bool was_frozen = c.element->isFreezeLabel();
+        if (was_frozen) c.element->freezeLabel(false);
+
+        c.element->rSequenceStruct() = seq;
+        c.element->setElementInformations(infos);
+        c.element->freezeLabel(frozen);
+    }
+}
diff --git a/sources/autoNum/renumberelementscommand.h b/sources/autoNum/renumberelementscommand.h
new file mode 100644
index 000000000..4c3d1c871
--- /dev/null
+++ b/sources/autoNum/renumberelementscommand.h
@@ -0,0 +1,70 @@
+/*
+    Copyright 2006-2026 The QElectroTech Team
+    This file is part of QElectroTech.
+
+    QElectroTech is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    QElectroTech is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RENUMBERELEMENTSCOMMAND_H
+#define RENUMBERELEMENTSCOMMAND_H
+
+#include <QUndoCommand>
+#include <QHash>
+#include <QVector>
+
+#include "../diagramcontext.h"
+#include "assignvariables.h" // defines autonum::sequentialNumbers
+
+class Element;
+class QETProject;
+
+/**
+ * @brief Undoable renumbering of element labels and sequence structs.
+ */
+class RenumberElementsCommand final : public QUndoCommand
+{
+public:
+    struct ElementChange
+    {
+        Element *element = nullptr;
+        DiagramContext old_infos;
+        DiagramContext new_infos;
+        autonum::sequentialNumbers old_seq;
+        autonum::sequentialNumbers new_seq;
+        bool old_frozen = false;
+        bool new_frozen = false;
+    };
+
+    RenumberElementsCommand(
+            QETProject *project,
+            QVector<ElementChange> changes,
+            QHash<QString, NumerotationContext> old_ctx,
+            QHash<QString, NumerotationContext> new_ctx,
+            const QString &text);
+
+    void undo() override;
+    void redo() override;
+
+private:
+    void apply(bool use_new);
+
+private:
+    QETProject *project_ = nullptr;
+    QVector<ElementChange> changes_;
+    QHash<QString, NumerotationContext> old_ctx_;
+    QHash<QString, NumerotationContext> new_ctx_;
+    bool first_redo_ = true;
+};
+
+#endif // RENUMBERELEMENTSCOMMAND_H
diff --git a/sources/autoNum/ui/autonumberingmanagementw.cpp b/sources/autoNum/ui/autonumberingmanagementw.cpp
index ba3e7f826..4e6499548 100644
--- a/sources/autoNum/ui/autonumberingmanagementw.cpp
+++ b/sources/autoNum/ui/autonumberingmanagementw.cpp
@@ -23,6 +23,7 @@
 #include "formulaautonumberingw.h"
 #include "numparteditorw.h"
 #include "qdebug.h"
+#include "renumberelementsdialog.h"
 #include "ui_autonumberingmanagementw.h"
 #include "ui_formulaautonumberingw.h"
 
@@ -48,6 +49,8 @@ AutoNumberingManagementW::AutoNumberingManagementW(QETProject *project,
 	ui->m_selected_folios_le->setDisabled(true);
 	ui->m_selected_folios_le->setReadOnly(true);
 	ui->m_apply_project_rb->setChecked(true);
+	// Enabled only when project is in "Under Development" status and not read-only.
+	ui->m_renumber_elements_pb->setEnabled(ui->m_status_cb->currentIndex() == 0 && project_ && !project_->isReadOnly());
 	setProjectContext();
 }
 
@@ -87,6 +90,7 @@ void AutoNumberingManagementW::on_m_status_cb_currentIndexChanged(int index)
 		ui->m_both_conductor_rb->setChecked(true);
 		ui->m_both_element_rb->setChecked(true);
 		ui->m_both_folio_rb->setChecked(true);
+		ui->m_renumber_elements_pb->setEnabled(true);
 	}
 	//Installing
 	else if (index == 1) {
@@ -96,15 +100,31 @@ void AutoNumberingManagementW::on_m_status_cb_currentIndexChanged(int index)
 		ui->m_new_conductor_rb->setChecked(true);
 		ui->m_new_element_rb->setChecked(true);
 		ui->m_new_folio_rb->setChecked(true);
+		ui->m_renumber_elements_pb->setEnabled(true);
 	}
 	//Built
 	else if (index == 2) {
 		ui->m_disable_conductor_rb->setChecked(true);
 		ui->m_disable_element_rb->setChecked(true);
 		ui->m_disable_folio_rb->setChecked(true);
+        	ui->m_renumber_elements_pb->setEnabled(false);
 	}
 }
 
+void AutoNumberingManagementW::on_m_renumber_elements_pb_clicked()
+{
+	if (!project_ || project_->isReadOnly()) return;
+	// Only allowed during "Under Development"
+	// if (ui->m_status_cb->currentIndex() != 1) return;
+
+	QStringList titles = project_->elementAutoNum().keys();
+	titles.sort(Qt::CaseInsensitive);
+	RenumberElementsDialog dlg(titles, this);
+	if (dlg.exec() != QDialog::Accepted) return;
+
+	project_->renumberElementsBySchemeTitle(dlg.selectedSchemeTitle());
+}
+
 /**
 	@brief AutoNumberingManagementW::on_m_apply_folios_rb_clicked
 	Set From Folios Combobox
diff --git a/sources/autoNum/ui/autonumberingmanagementw.h b/sources/autoNum/ui/autonumberingmanagementw.h
index 5ecb6841a..c5893544e 100644
--- a/sources/autoNum/ui/autonumberingmanagementw.h
+++ b/sources/autoNum/ui/autonumberingmanagementw.h
@@ -50,6 +50,7 @@ class AutoNumberingManagementW : public QWidget
 		void on_m_from_folios_cb_currentIndexChanged(int);
 		void on_m_to_folios_cb_currentIndexChanged(int);
 		void on_m_status_cb_currentIndexChanged(int);
+		void on_m_renumber_elements_pb_clicked();
 		void on_m_apply_folios_rb_clicked();
 		void on_m_apply_project_rb_clicked();
 		void on_buttonBox_clicked(QAbstractButton *);
diff --git a/sources/autoNum/ui/autonumberingmanagementw.ui b/sources/autoNum/ui/autonumberingmanagementw.ui
index be70d22b6..7099bcef7 100644
--- a/sources/autoNum/ui/autonumberingmanagementw.ui
+++ b/sources/autoNum/ui/autonumberingmanagementw.ui
@@ -308,6 +308,13 @@
            </property>
           </widget>
          </item>
+        <item>
+         <widget class="QPushButton" name="m_renumber_elements_pb">
+          <property name="text">
+           <string>Renumber element(s)…</string>
+          </property>
+         </widget>
+        </item>
          <item>
           <spacer name="horizontalSpacer_2">
            <property name="orientation">
diff --git a/sources/autoNum/ui/renumberelementsdialog.cpp b/sources/autoNum/ui/renumberelementsdialog.cpp
new file mode 100644
index 000000000..a8c4c9dd1
--- /dev/null
+++ b/sources/autoNum/ui/renumberelementsdialog.cpp
@@ -0,0 +1,75 @@
+/*
+    Copyright 2006-2026 The QElectroTech Team
+    This file is part of QElectroTech.
+
+    QElectroTech is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    QElectroTech is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#include "renumberelementsdialog.h"
+
+#include <QComboBox>
+#include <QDialogButtonBox>
+#include <QFormLayout>
+#include <QGroupBox>
+#include <QHBoxLayout>
+#include <QLabel>
+#include <QRadioButton>
+#include <QVBoxLayout>
+
+RenumberElementsDialog::RenumberElementsDialog(const QStringList &scheme_titles, QWidget *parent)
+    : QDialog(parent)
+    , m_scheme_titles(scheme_titles)
+{
+    setWindowTitle(tr("Renumber element(s)"));
+    setModal(true);
+
+    auto *vl = new QVBoxLayout(this);
+
+    auto *scope = new QGroupBox(tr("Scope"), this);
+    auto *scope_l = new QVBoxLayout(scope);
+    m_all_rb = new QRadioButton(tr("All schemes"), scope);
+    m_one_rb = new QRadioButton(tr("One scheme"), scope);
+    scope_l->addWidget(m_all_rb);
+    scope_l->addWidget(m_one_rb);
+    vl->addWidget(scope);
+
+    auto *form = new QFormLayout();
+    m_combo = new QComboBox(this);
+    m_combo->addItems(m_scheme_titles);
+    form->addRow(new QLabel(tr("Scheme:"), this), m_combo);
+    vl->addLayout(form);
+
+    m_buttons = new QDialogButtonBox(QDialogButtonBox::Ok | QDialogButtonBox::Cancel, this);
+    connect(m_buttons, &QDialogButtonBox::accepted, this, &QDialog::accept);
+    connect(m_buttons, &QDialogButtonBox::rejected, this, &QDialog::reject);
+    vl->addWidget(m_buttons);
+
+    m_all_rb->setChecked(true);
+    updateUi();
+
+    connect(m_all_rb, &QRadioButton::toggled, this, &RenumberElementsDialog::updateUi);
+    connect(m_one_rb, &QRadioButton::toggled, this, &RenumberElementsDialog::updateUi);
+}
+
+QString RenumberElementsDialog::selectedSchemeTitle() const
+{
+    if (m_all_rb && m_all_rb->isChecked()) return QString();
+    return m_combo ? m_combo->currentText() : QString();
+}
+
+void RenumberElementsDialog::updateUi()
+{
+    const bool one = m_one_rb && m_one_rb->isChecked();
+    if (m_combo) m_combo->setEnabled(one);
+}
diff --git a/sources/autoNum/ui/renumberelementsdialog.h b/sources/autoNum/ui/renumberelementsdialog.h
new file mode 100644
index 000000000..8a49fac93
--- /dev/null
+++ b/sources/autoNum/ui/renumberelementsdialog.h
@@ -0,0 +1,59 @@
+/*
+    Copyright 2006-2026 The QElectroTech Team
+    This file is part of QElectroTech.
+
+    QElectroTech is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 2 of the License, or
+    (at your option) any later version.
+
+    QElectroTech is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with QElectroTech.  If not, see <http://www.gnu.org/licenses/>.
+*/
+
+#ifndef RENUMBERELEMENTSDIALOG_H
+#define RENUMBERELEMENTSDIALOG_H
+
+#include <QDialog>
+#include <QStringList>
+
+class QComboBox;
+class QRadioButton;
+class QDialogButtonBox;
+
+/**
+ * @brief Simple dialog to pick renumbering scope for elements.
+ *
+ * The user can choose between:
+ *  - all element autonumbering schemes
+ *  - one selected scheme title
+ */
+class RenumberElementsDialog final : public QDialog
+{
+    Q_OBJECT
+
+public:
+    explicit RenumberElementsDialog(const QStringList &scheme_titles, QWidget *parent = nullptr);
+
+    /**
+     * @return Empty string if "all" is selected, otherwise the chosen scheme title.
+     */
+    QString selectedSchemeTitle() const;
+
+private slots:
+    void updateUi();
+
+private:
+    QStringList m_scheme_titles;
+    QRadioButton *m_all_rb = nullptr;
+    QRadioButton *m_one_rb = nullptr;
+    QComboBox *m_combo = nullptr;
+    QDialogButtonBox *m_buttons = nullptr;
+};
+
+#endif // RENUMBERELEMENTSDIALOG_H
diff --git a/sources/qetproject.cpp b/sources/qetproject.cpp
index d296ebf74..66f1c1b5b 100644
--- a/sources/qetproject.cpp
+++ b/sources/qetproject.cpp
@@ -22,7 +22,9 @@
 #include "autoNum/assignvariables.h"
 #include "autoNum/numerotationcontext.h"
 #include "autoNum/numerotationcontextcommands.h"
+#include "autoNum/renumberelementscommand.h"
 #include "diagram.h"
+#include "qetgraphicsitem/element.h"
 #include "qetapp.h"
 #include "qetmessagebox.h"
 #include "qetresult.h"
@@ -40,7 +42,30 @@
 #include <QHash>
 #include <QTimer>
 #include <QtConcurrentRun>
+
+namespace {
+
+/**
+ * @brief Reset numeric fields of a NumerotationContext so renumbering starts at 1.
+ * Keeps non-numeric parts (string/idfolio/folio/plant/locmach/elementline/elementcolumn/elementprefix) unchanged.
+ */
+NumerotationContext resetContextForRenumber(const NumerotationContext &tmpl)
+{
+	NumerotationContext out = tmpl;
+	for (int i = 0; i < out.size(); ++i) {
+		const QStringList parts = out.itemAt(i);
+		if (parts.isEmpty()) continue;
+		const QString type = parts.at(0);
+		if (out.keyIsNumber(type)) {
+			out.replaceValue(i, QStringLiteral("1"));
+		}
+	}
+	return out;
+}
+
+} // namespace
 #include <QtDebug>
+#include <algorithm>
 #include <utility>
 
 static int BACKUP_INTERVAL = 1200000; //interval in ms of backup = 20min
@@ -682,6 +707,109 @@ void QETProject::setCurrrentElementAutonum(QString autoNum) {
 	m_current_element_autonum = std::move(autoNum);
 }
 
+/**
+	@brief QETProject::renumberElementsBySchemeTitle
+	Renumber existing elements by element autonumbering scheme title.
+
+	Elements do not store the scheme title; they store a "formula" (elementInformations["formula"]).
+	This method matches elements to schemes by comparing the stored formula with the formula derived
+	from each scheme's NumerotationContext.
+
+	If scheme_title is empty, all schemes are renumbered. Otherwise only that scheme is renumbered.
+	The operation is undoable.
+*/
+void QETProject::renumberElementsBySchemeTitle(const QString &scheme_title)
+{
+	if (!m_undo_stack) return;
+	if (isReadOnly()) return;
+
+	// Build map: scheme title -> canonical formula
+	QHash<QString, QString> scheme_formula;
+	for (const QString &k : m_element_autonum.keys()) {
+		if (!scheme_title.isEmpty() && k != scheme_title) continue;
+		scheme_formula.insert(k, autonum::numerotationContextToFormula(m_element_autonum.value(k)));
+	}
+	if (scheme_formula.isEmpty()) return;
+
+	// Collect elements per scheme by formula match
+	QHash<QString, QVector<Element*>> by_key;
+	for (Diagram *d : diagrams()) {
+		if (!d) continue;
+		const auto items = d->items();
+		for (QGraphicsItem *it : items) {
+			auto *el = qgraphicsitem_cast<Element*>(it);
+			if (!el) continue;
+			if (el->linkType() == Element::Slave || (el->linkType() & Element::AllReport))
+				continue;
+
+			const QString el_formula = el->elementInformations().value(QStringLiteral("formula")).toString();
+			if (el_formula.isEmpty()) continue;
+
+			QString matched_key;
+			for (auto itf = scheme_formula.constBegin(); itf != scheme_formula.constEnd(); ++itf) {
+				if (itf.value() == el_formula) { matched_key = itf.key(); break; }
+			}
+			if (matched_key.isEmpty()) continue;
+			by_key[matched_key].append(el);
+		}
+	}
+	if (by_key.isEmpty()) return;
+
+	QVector<RenumberElementsCommand::ElementChange> changes;
+	QHash<QString, NumerotationContext> old_ctx;
+	QHash<QString, NumerotationContext> new_ctx;
+
+	for (auto it = by_key.constBegin(); it != by_key.constEnd(); ++it) {
+		old_ctx.insert(it.key(), m_element_autonum.value(it.key()));
+	}
+
+	for (auto it = by_key.begin(); it != by_key.end(); ++it) {
+		const QString key = it.key();
+		auto &elements = it.value();
+		std::sort(elements.begin(), elements.end(), [](Element *a, Element *b){ return comparPos(a, b); });
+
+		NumerotationContext base_tmpl = m_element_autonum.value(key);
+		NumerotationContext nc = resetContextForRenumber(base_tmpl);
+		NumerotationContextCommands ncc(nc);
+
+		for (Element *el : elements) {
+			RenumberElementsCommand::ElementChange ch;
+			ch.element = el;
+			ch.old_infos = el->elementInformations();
+			ch.old_seq = el->sequenceStruct();
+			ch.old_frozen = el->isFreezeLabel();
+			ch.new_frozen = ch.old_frozen; // preserve frozen state
+
+			const QString formula = ch.old_infos.value(QStringLiteral("formula")).toString();
+			autonum::sequentialNumbers new_seq;
+			new_seq.clear();
+			autonum::setSequential(formula, new_seq, nc, el->diagram(), key);
+
+			DiagramContext new_infos = ch.old_infos;
+			new_infos.addValue(QStringLiteral("label"), autonum::AssignVariables::formulaToLabel(formula, new_seq, el->diagram(), el, nullptr));
+			ch.new_infos = new_infos;
+			ch.new_seq = new_seq;
+			changes.append(ch);
+
+			// advance
+			nc = ncc.next();
+			ncc = NumerotationContextCommands(nc);
+		}
+
+		new_ctx.insert(key, nc);
+	}
+
+	if (changes.isEmpty()) return;
+
+	auto *cmd = new RenumberElementsCommand(
+			this,
+			changes,
+			old_ctx,
+			new_ctx,
+			scheme_title.isEmpty() ? tr("Renumber elements") : tr("Renumber elements (%1)").arg(scheme_title));
+	m_undo_stack->push(cmd);
+}
+
 /**
 	@brief QETProject::conductorAutoNumFormula
 	@param key : autonum title
diff --git a/sources/qetproject.h b/sources/qetproject.h
index 3817abad9..2c968f9d5 100644
--- a/sources/qetproject.h
+++ b/sources/qetproject.h
@@ -169,6 +169,20 @@ class QETProject : public QObject
 		QString elementCurrentAutoNum() const;
 		void setCurrrentElementAutonum(QString autoNum);
 
+		/**
+		 * @brief Renumber existing elements by element autonumbering scheme.
+		 *
+		 * Elements do not store the scheme title but they store the corresponding formula.
+		 * This operation matches elements to schemes by comparing the stored formula
+		 * with the formula derived from the scheme's NumerotationContext.
+		 *
+		 * If @p scheme_title is empty, all schemes are renumbered.
+		 * If @p scheme_title is non-empty, only that scheme is renumbered.
+		 *
+		 * The operation is undoable.
+		 */
+		void renumberElementsBySchemeTitle(const QString &scheme_title = QString());
+
 			//Element
 		void freezeExistentElementLabel(bool freeze, int from, int to);
 		void freezeNewElementLabel(bool freeze, int from, int to);