diff --git a/src/debug.cpp b/src/debug.cpp
index aa06f0f8..fad9c6f6 100644
--- a/src/debug.cpp
+++ b/src/debug.cpp
@@ -19,10 +19,15 @@ unsigned int debuggerPageSize = 14;
 int vblankScanLines = 0;	//Used to calculate scanlines 240-261 (vblank)
 int vblankPixel = 0;		//Used to calculate the pixels in vblank
 
-int offsetStringToInt(unsigned int type, const char* offsetBuffer)
+int offsetStringToInt(unsigned int type, const char* offsetBuffer, bool *conversionOk)
 {
 	int offset = -1;
 
+	if (conversionOk)
+	{
+		*conversionOk = false;
+	}
+
 	if (sscanf(offsetBuffer,"%7X",(unsigned int *)&offset) == EOF)
 	{
 		return -1;
@@ -30,14 +35,26 @@ int offsetStringToInt(unsigned int type, const char* offsetBuffer)
 
 	if (type & BT_P)
 	{
+		if (conversionOk)
+		{
+			*conversionOk = (offset >= 0) && (offset < 0x4000);
+		}
 		return offset & 0x3FFF;
 	}
 	else if (type & BT_S)
 	{
+		if (conversionOk)
+		{
+			*conversionOk = (offset >= 0) && (offset < 0x100);
+		}
 		return offset & 0x00FF;
 	}
 	else if (type & BT_R)
 	{
+		if (conversionOk)
+		{
+			*conversionOk = (offset >= 0);
+		}
 		return offset;
 	}
 	else // BT_C
@@ -46,6 +63,10 @@ int offsetStringToInt(unsigned int type, const char* offsetBuffer)
 
 		if (sym)
 		{
+			if (conversionOk)
+			{
+				*conversionOk = true;
+			}
 			return sym->offset() & 0xFFFF;
 		}
 
@@ -56,21 +77,26 @@ int offsetStringToInt(unsigned int type, const char* offsetBuffer)
 			type = GameInfo->type;
 		}
 		if (type == GIT_NSF) { //NSF Breakpoint keywords
-			if (strcmp(offsetBuffer,"LOAD") == 0) return (NSFHeader.LoadAddressLow | (NSFHeader.LoadAddressHigh<<8));
-			if (strcmp(offsetBuffer,"INIT") == 0) return (NSFHeader.InitAddressLow | (NSFHeader.InitAddressHigh<<8));
-			if (strcmp(offsetBuffer,"PLAY") == 0) return (NSFHeader.PlayAddressLow | (NSFHeader.PlayAddressHigh<<8));
+			if (strcmp(offsetBuffer,"LOAD") == 0) offset = (NSFHeader.LoadAddressLow | (NSFHeader.LoadAddressHigh<<8));
+			else if (strcmp(offsetBuffer,"INIT") == 0) offset = (NSFHeader.InitAddressLow | (NSFHeader.InitAddressHigh<<8));
+			else if (strcmp(offsetBuffer,"PLAY") == 0) offset = (NSFHeader.PlayAddressLow | (NSFHeader.PlayAddressHigh<<8));
 		}
 		else if (type == GIT_FDS) { //FDS Breakpoint keywords
-			if (strcmp(offsetBuffer,"NMI1") == 0) return (GetMem(0xDFF6) | (GetMem(0xDFF7)<<8));
-			if (strcmp(offsetBuffer,"NMI2") == 0) return (GetMem(0xDFF8) | (GetMem(0xDFF9)<<8));
-			if (strcmp(offsetBuffer,"NMI3") == 0) return (GetMem(0xDFFA) | (GetMem(0xDFFB)<<8));
-			if (strcmp(offsetBuffer,"RST") == 0) return (GetMem(0xDFFC) | (GetMem(0xDFFD)<<8));
-			if ((strcmp(offsetBuffer,"IRQ") == 0) || (strcmp(offsetBuffer,"BRK") == 0)) return (GetMem(0xDFFE) | (GetMem(0xDFFF)<<8));
+			if (strcmp(offsetBuffer,"NMI1") == 0) offset = (GetMem(0xDFF6) | (GetMem(0xDFF7)<<8));
+			else if (strcmp(offsetBuffer,"NMI2") == 0) offset = (GetMem(0xDFF8) | (GetMem(0xDFF9)<<8));
+			else if (strcmp(offsetBuffer,"NMI3") == 0) offset = (GetMem(0xDFFA) | (GetMem(0xDFFB)<<8));
+			else if (strcmp(offsetBuffer,"RST") == 0) offset = (GetMem(0xDFFC) | (GetMem(0xDFFD)<<8));
+			else if ((strcmp(offsetBuffer,"IRQ") == 0) || (strcmp(offsetBuffer,"BRK") == 0)) offset = (GetMem(0xDFFE) | (GetMem(0xDFFF)<<8));
 		}
 		else { //NES Breakpoint keywords
-			if ((strcmp(offsetBuffer,"NMI") == 0) || (strcmp(offsetBuffer,"VBL") == 0)) return (GetMem(0xFFFA) | (GetMem(0xFFFB)<<8));
-			if (strcmp(offsetBuffer,"RST") == 0) return (GetMem(0xFFFC) | (GetMem(0xFFFD)<<8));
-			if ((strcmp(offsetBuffer,"IRQ") == 0) || (strcmp(offsetBuffer,"BRK") == 0)) return (GetMem(0xFFFE) | (GetMem(0xFFFF)<<8));
+			if ((strcmp(offsetBuffer,"NMI") == 0) || (strcmp(offsetBuffer,"VBL") == 0)) offset = (GetMem(0xFFFA) | (GetMem(0xFFFB)<<8));
+			else if (strcmp(offsetBuffer,"RST") == 0) offset = (GetMem(0xFFFC) | (GetMem(0xFFFD)<<8));
+			else if ((strcmp(offsetBuffer,"IRQ") == 0) || (strcmp(offsetBuffer,"BRK") == 0)) offset = (GetMem(0xFFFE) | (GetMem(0xFFFF)<<8));
+		}
+
+		if (conversionOk)
+		{
+			*conversionOk = (offset >= 0) && (offset < 0x10000);
 		}
 	}
 
diff --git a/src/debug.h b/src/debug.h
index e1d8b573..708c12ef 100644
--- a/src/debug.h
+++ b/src/debug.h
@@ -172,7 +172,7 @@ DebuggerState &FCEUI_Debugger();
 //#define WRITE_BREAKPOINT 16
 //#define EXECUTE_BREAKPOINT 32
 
-int offsetStringToInt(unsigned int type, const char* offsetBuffer);
+int offsetStringToInt(unsigned int type, const char* offsetBuffer, bool *conversionOk = nullptr);
 unsigned int NewBreak(const char* name, int start, int end, unsigned int type, const char* condition, unsigned int num, bool enable);
 
 #endif
diff --git a/src/drivers/Qt/ConsoleDebugger.cpp b/src/drivers/Qt/ConsoleDebugger.cpp
index 20c06510..33e9d096 100644
--- a/src/drivers/Qt/ConsoleDebugger.cpp
+++ b/src/drivers/Qt/ConsoleDebugger.cpp
@@ -1872,6 +1872,9 @@ DebuggerBreakpointEditor::DebuggerBreakpointEditor(int editIndex, watchpointinfo
 	hbox->addWidget( lbl );
 	hbox->addWidget( addr2 );
 
+	connect( addr1, SIGNAL(textChanged(const QString &)), this, SLOT(addressTextChanged(const QString &)));
+	connect( addr2, SIGNAL(textChanged(const QString &)), this, SLOT(addressTextChanged(const QString &)));
+
 	forbidChkBox = new QCheckBox( tr("Forbid") );
 	hbox->addWidget( forbidChkBox );
 
@@ -1904,6 +1907,11 @@ DebuggerBreakpointEditor::DebuggerBreakpointEditor(int editIndex, watchpointinfo
 	rom_radio    = new QRadioButton( tr("ROM") );
 	cpu_radio->setChecked(true);
 
+	connect( cpu_radio, SIGNAL(toggled(bool)), this, SLOT(typeChanged(bool)));
+	connect( ppu_radio, SIGNAL(toggled(bool)), this, SLOT(typeChanged(bool)));
+	connect( oam_radio, SIGNAL(toggled(bool)), this, SLOT(typeChanged(bool)));
+	connect( rom_radio, SIGNAL(toggled(bool)), this, SLOT(typeChanged(bool)));
+
 	gbox->setLayout( hbox );
 	hbox->addWidget( cpu_radio );
 	hbox->addWidget( ppu_radio );
@@ -2069,7 +2077,73 @@ void DebuggerBreakpointEditor::closeWindow(int ret)
 //----------------------------------------------------------------------------
 void DebuggerBreakpointEditor::checkDataValid(void)
 {
-	bool allEntriesValid = condValid;
+	int type = 0;
+	bool startAddrValid = false;
+	bool endAddrValid = false;
+	bool allEntriesValid = false;
+	int addrLowerBound = 0;
+	int addrUpperBound = 0;
+	int start_addr = 0, end_addr = 0;
+
+	if ( cpu_radio->isChecked() )
+	{
+		type |= BT_C;
+		addrLowerBound = 0;
+		addrUpperBound = 0x10000;
+	}
+	else if ( ppu_radio->isChecked() ) 
+	{
+		type |= BT_P;
+		addrLowerBound = 0;
+		addrUpperBound = 0x4000;
+	}
+	else if ( oam_radio->isChecked() ) 
+	{
+		type |= BT_S;
+		addrLowerBound = 0;
+		addrUpperBound = 0x100;
+	}
+	else if ( rom_radio->isChecked() )
+	{
+		type |= BT_R;
+		addrLowerBound = 0;
+		addrUpperBound = 0x10000;
+
+		if (GameInfo != nullptr)
+		{
+			addrUpperBound = 16+PRGsize[0]+CHRsize[0];
+		}
+	}
+
+	if ( addr1->text().size() > 0 )
+	{
+		bool convOk = false;
+
+		start_addr = offsetStringToInt( type, addr1->text().toStdString().c_str(), &convOk );
+
+		//printf("StartAddr:0x%04X   Upper:0x%04X\n", start_addr, addrUpperBound);
+		startAddrValid = convOk && (start_addr >= addrLowerBound) && (start_addr < addrUpperBound);
+	}
+	else
+	{
+		startAddrValid = false;
+	}
+
+	if ( addr2->text().size() > 0 )
+	{
+		bool convOk = false;
+
+		end_addr = offsetStringToInt( type, addr2->text().toStdString().c_str(), &convOk );
+
+		endAddrValid = convOk && (end_addr >= addrLowerBound) && 
+			(end_addr < addrUpperBound) && (start_addr < end_addr);
+	}
+	else
+	{
+		endAddrValid = true;
+	}
+
+	allEntriesValid = startAddrValid && endAddrValid && condValid;
 
 	okButton->setEnabled( allEntriesValid );
 
@@ -2077,6 +2151,14 @@ void DebuggerBreakpointEditor::checkDataValid(void)
 	{
 		msgLbl->clear();
 	}
+	else if (!startAddrValid)
+	{
+		msgLbl->setText(tr("Start Address Invalid"));
+	}
+	else if (!endAddrValid)
+	{
+		msgLbl->setText(tr("End Address Invalid"));
+	}
 	else if (!condValid)
 	{
 		msgLbl->setText(tr("Condition Invalid"));
@@ -2087,6 +2169,19 @@ void DebuggerBreakpointEditor::checkDataValid(void)
 	}
 }
 //----------------------------------------------------------------------------
+void DebuggerBreakpointEditor::typeChanged(bool checked)
+{
+	if (checked)
+	{
+		checkDataValid();
+	}
+}
+//----------------------------------------------------------------------------
+void DebuggerBreakpointEditor::addressTextChanged(const QString &txt)
+{
+	checkDataValid();
+}
+//----------------------------------------------------------------------------
 void DebuggerBreakpointEditor::conditionTextChanged(const QString &txt)
 {
 	if ( txt.size() > 0 )
diff --git a/src/drivers/Qt/ConsoleDebugger.h b/src/drivers/Qt/ConsoleDebugger.h
index 5d55003f..fec0a8dd 100644
--- a/src/drivers/Qt/ConsoleDebugger.h
+++ b/src/drivers/Qt/ConsoleDebugger.h
@@ -460,6 +460,8 @@ class DebuggerBreakpointEditor : public QDialog
 
 	private slots:
 		void closeWindow(int ret);
+		void typeChanged(bool checked);
+		void addressTextChanged( const QString &text );
 		void conditionTextChanged( const QString &text );
 };