diff --git a/src/cmd_context/context_params.cpp b/src/cmd_context/context_params.cpp
index 41ad5a423..6d9222a37 100644
--- a/src/cmd_context/context_params.cpp
+++ b/src/cmd_context/context_params.cpp
@@ -41,7 +41,7 @@ void context_params::set_bool(bool & opt, char const * param, char const * value
 
 void context_params::set(char const * param, char const * value) {
     std::string p = param;
-    unsigned n = p.size();
+    unsigned n = static_cast<unsigned>(p.size());
     for (unsigned i = 0; i < n; i++) {
         if (p[i] >= 'A' && p[i] <= 'Z')
             p[i] = p[i] - 'A' + 'a';
diff --git a/src/util/gparams.cpp b/src/util/gparams.cpp
index b81531798..1305a1e02 100644
--- a/src/util/gparams.cpp
+++ b/src/util/gparams.cpp
@@ -165,7 +165,7 @@ public:
         if (*name == ':')
             name++;
         std::string tmp = name;
-        unsigned n = tmp.size();
+        unsigned n = static_cast<unsigned>(tmp.size());
         for (unsigned i = 0; i < n; i++) {
             if (tmp[i] >= 'A' && tmp[i] <= 'Z')
                 tmp[i] = tmp[i] - 'A' + 'a';
diff --git a/src/util/params.cpp b/src/util/params.cpp
index d9878c70a..0ee42868d 100644
--- a/src/util/params.cpp
+++ b/src/util/params.cpp
@@ -29,7 +29,7 @@ std::string norm_param_name(char const * n) {
     if (*n == ':')
         n++;
     std::string r = n;
-    unsigned sz = r.size();
+    unsigned sz = static_cast<unsigned>(r.size());
     if (sz == 0)
         return "_";
     for (unsigned i = 0; i < sz; i++) {
@@ -135,7 +135,7 @@ struct param_descrs::imp {
             if (smt2_style)
                 out << ':';
             char const * s = it2->bare_str();
-            unsigned n = strlen(s);
+            unsigned n = static_cast<unsigned>(strlen(s));
             for (unsigned i = 0; i < n; i++) {
                 if (smt2_style && s[i] == '_')
                     out << '-';