diff --git a/src/asciiview.cpp b/src/asciiview.cpp
index 1a5dd18..c7e2816 100644
--- a/src/asciiview.cpp
+++ b/src/asciiview.cpp
@@ -73,9 +73,11 @@ QString AsciiView::hexDump(const QVector<unsigned char> &data) {
         QString line;
         line += QString("%1  ").arg(offset, 8, 16, QChar('0')).toUpper();
         offset += 16;
-        for (int j = 0; j < 16; ++j) {
+        for (qsizetype j = 0; j < 16; ++j) {
             if (i + j < dataSize) {
-                line += QString("%1 ").arg(static_cast<unsigned char>(data[i + j]), 2, 16, QChar('0')).toUpper();
+                line += QString("%1 ")
+                .arg(static_cast<unsigned char>(data[static_cast<int>(i + j)]), 2, 16, QChar('0'))
+                    .toUpper();
             } else {
                 line += "   ";
             }
@@ -83,8 +85,8 @@ QString AsciiView::hexDump(const QVector<unsigned char> &data) {
         }
 
         line += " ";
-        for (int j = 0; j < 16 && i + j < dataSize; ++j) {
-            unsigned char c = data[i + j];
+        for (qsizetype j = 0; j < 16 && i + j < dataSize; ++j) {
+            unsigned char c = data[static_cast<int>(i + j)];
             line += (c >= 32 && c <= 126) ? QChar::fromLatin1(static_cast<char>(c)) : QChar('.');
         }
         result += line + "\n";
diff --git a/src/jsonparser.cpp b/src/jsonparser.cpp
index 98e2317..8503ba9 100644
--- a/src/jsonparser.cpp
+++ b/src/jsonparser.cpp
@@ -34,8 +34,9 @@ QVector<QPair<QString, int>> JsonParser::parse(const QString &json)
             }
             qsizetype colonPos = trimmedLine.indexOf(":");
             if (colonPos != -1) {
-                QString key = removeQuotes(trimmedLine.left(colonPos));
-                QString valueString = trimmedLine.mid(colonPos + 1).trimmed();
+                int pos = static_cast<int>(colonPos);
+                QString key = removeQuotes(trimmedLine.left(pos));
+                QString valueString = trimmedLine.mid(pos + 1).trimmed();
                 valueString.chop(1);
                 int value = valueString.toInt();
                 data.append(qMakePair(key, value));
diff --git a/src/utils.cpp b/src/utils.cpp
index 1b52780..ae4416e 100644
--- a/src/utils.cpp
+++ b/src/utils.cpp
@@ -115,15 +115,15 @@ QPair<QStringList, QJsonArray> utils::scanDevices(bool initializing)
 
     static const QRegularExpression regex("\\}\\n\\{");
 
-    while ((endIndex = allDevicesOutput.indexOf(regex, startIndex)) != -1) {
+    while ((endIndex = allDevicesOutput.indexOf(regex, static_cast<int>(startIndex))) != -1) {
         ++endIndex;
-        QString jsonFragment = allDevicesOutput.mid(startIndex, endIndex - startIndex);
+        QString jsonFragment = allDevicesOutput.mid(static_cast<int>(startIndex), static_cast<int>(endIndex - startIndex));
         deviceOutputs.append(jsonFragment);
         startIndex = endIndex;
     }
 
     if (startIndex < allDevicesOutput.size()) {
-        QString jsonFragment = allDevicesOutput.mid(startIndex);
+        QString jsonFragment = allDevicesOutput.mid(static_cast<int>(startIndex));
         deviceOutputs.append(jsonFragment);
     }