diff --git a/sources/conductorproperties.cpp b/sources/conductorproperties.cpp
index 12a55539c..6cf2f40fd 100644
--- a/sources/conductorproperties.cpp
+++ b/sources/conductorproperties.cpp
@@ -436,7 +436,10 @@ void ConductorProperties::fromSettings(QSettings &settings, const QString &prefi
 	m_wire_color         = settings.value(prefix + "conductor_color", "").toString();
 	m_wire_section       = settings.value(prefix + "conductor_section", "").toString();
 	text_size            = settings.value(prefix + "textsize", "7").toInt();
-	cond_size            = settings.value(prefix + "size", "1").toInt();
+		// Saved with QString::number(cond_size): a decimal such as 1.4,
+		// which toInt() would read as 0.
+	cond_size            = settings.value(prefix + "size", "1").toDouble();
+	if (!qIsFinite(cond_size) || cond_size <= 0) cond_size = 1;
 	m_show_text          = settings.value(prefix + "displaytext", true).toBool();
 	m_one_text_per_folio = settings.value(prefix + "onetextperfolio", false).toBool();
 	verti_rotate_text    = settings.value((prefix + "vertirotatetext"), "270").toDouble();
diff --git a/tests/qttest/CMakeLists.txt b/tests/qttest/CMakeLists.txt
index d20eb3711..1af0799b1 100644
--- a/tests/qttest/CMakeLists.txt
+++ b/tests/qttest/CMakeLists.txt
@@ -947,6 +947,19 @@ add_test(NAME tst_conductorapplychanges COMMAND tst_conductorapplychanges)
 target_include_directories(tst_conductorapplychanges PRIVATE ${QET_DIR}/sources)
 target_link_libraries(tst_conductorapplychanges PRIVATE Qt::Test Qt::Widgets Qt::Xml pugixml::pugixml)
 
+# ConductorProperties::fromSettings() -- the default conductor width is a
+# decimal and comes back as saved (1.4 used to be read as 0).
+add_executable(
+  tst_conductorsizesetting
+  tst_conductorsizesetting.cpp
+  ${QET_DIR}/sources/conductorproperties.cpp
+  ${QET_DIR}/sources/qet.cpp
+  ${QET_DIR}/sources/qeticons.cpp
+  ${QET_DIR}/sources/shortcutmanager.cpp)
+add_test(NAME tst_conductorsizesetting COMMAND tst_conductorsizesetting)
+target_include_directories(tst_conductorsizesetting PRIVATE ${QET_DIR}/sources)
+target_link_libraries(tst_conductorsizesetting PRIVATE Qt::Test Qt::Widgets Qt::Xml pugixml::pugixml)
+
 # ConductorMultiEdit -- editing several wires at once in the Selection
 # properties panel: order, which wires an edit reaches, one undo step for
 # all of them, and fields shown blank because the wires disagree.
diff --git a/tests/qttest/tst_conductorsizesetting.cpp b/tests/qttest/tst_conductorsizesetting.cpp
new file mode 100644
index 000000000..7a8afbeac
--- /dev/null
+++ b/tests/qttest/tst_conductorsizesetting.cpp
@@ -0,0 +1,113 @@
+/*
+	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 "conductorproperties.h"
+#include "qetapp.h"
+
+#include <QtTest>
+#include <QSettings>
+
+// qet.cpp, compiled in for ConductorProperties, refers to this static.
+QString QETApp::m_interface_language;
+
+/**
+	ConductorProperties::toSettings()/fromSettings() keep the conductor
+	width (cond_size) as it was saved. The width is a decimal, written with
+	QString::number(); reading it with toInt() gave 0 for every value that
+	was not a whole number, so a default width of 1.4 came back as 0 after
+	a restart.
+
+	This test owns its own QSettings scope (organization + application
+	name), so it cannot read or write the configuration of whoever runs it.
+*/
+class tst_conductorsizesetting : public QObject
+{
+	Q_OBJECT
+
+private slots:
+	void initTestCase()
+	{
+		QCoreApplication::setOrganizationName(
+					QStringLiteral("QElectroTech-tst_conductorsizesetting"));
+		QCoreApplication::setApplicationName(QStringLiteral("tst_conductorsizesetting"));
+		QSettings settings;
+		settings.clear();
+	}
+
+	void init()
+	{
+		QSettings settings;
+		settings.clear();
+		settings.sync();
+	}
+
+	void widthSurvivesARoundTrip_data()
+	{
+		QTest::addColumn<qreal>("width");
+		QTest::newRow("whole number") << 2.0;
+		QTest::newRow("decimal")      << 1.4;
+		QTest::newRow("minimum")      << 0.4;
+		QTest::newRow("rounds down")  << 61.3;
+		QTest::newRow("rounds up")    << 61.7;
+	}
+
+	void widthSurvivesARoundTrip()
+	{
+		QFETCH(qreal, width);
+		QSettings settings;
+		ConductorProperties saved;
+		saved.cond_size = width;
+		saved.toSettings(settings, QStringLiteral("test/"));
+
+		ConductorProperties loaded;
+		loaded.fromSettings(settings, QStringLiteral("test/"));
+		QCOMPARE(loaded.cond_size, width);
+	}
+
+	// A hand-edited or truncated settings file must not give a width of 0.
+	void unusableValueFallsBackToOne_data()
+	{
+		QTest::addColumn<QString>("value");
+		QTest::newRow("text")     << QStringLiteral("wide");
+		QTest::newRow("zero")     << QStringLiteral("0");
+		QTest::newRow("negative") << QStringLiteral("-1");
+		QTest::newRow("nan")      << QStringLiteral("nan");
+		QTest::newRow("inf")      << QStringLiteral("inf");
+	}
+
+	void unusableValueFallsBackToOne()
+	{
+		QFETCH(QString, value);
+		QSettings settings;
+		settings.setValue(QStringLiteral("test/size"), value);
+
+		ConductorProperties loaded;
+		loaded.fromSettings(settings, QStringLiteral("test/"));
+		QCOMPARE(loaded.cond_size, 1.0);
+	}
+
+	void missingValueIsOne()
+	{
+		QSettings settings;
+		ConductorProperties loaded;
+		loaded.fromSettings(settings, QStringLiteral("test/"));
+		QCOMPARE(loaded.cond_size, 1.0);
+	}
+};
+
+QTEST_GUILESS_MAIN(tst_conductorsizesetting)
+#include "tst_conductorsizesetting.moc"