diff --git a/include/omath/linear_algebra/mat.hpp b/include/omath/linear_algebra/mat.hpp
index 6f5dfd8..4f5a7ed 100644
--- a/include/omath/linear_algebra/mat.hpp
+++ b/include/omath/linear_algebra/mat.hpp
@@ -158,19 +158,19 @@ namespace omath
             Mat<Rows, OtherColumns, Type, StoreType> result;
 
             if constexpr (StoreType == MatStoreType::ROW_MAJOR)
-                for (size_t i = 0; i < Rows; ++i)
-                    for (size_t k = 0; k < Columns; ++k)
+                for (std::size_t i = 0; i < Rows; ++i)
+                    for (std::size_t k = 0; k < Columns; ++k)
                     {
                         const Type aik = at(i, k);
-                        for (size_t j = 0; j < OtherColumns; ++j)
+                        for (std::size_t j = 0; j < OtherColumns; ++j)
                             result.at(i, j) += aik * other.at(k, j);
                     }
             else if constexpr (StoreType == MatStoreType::COLUMN_MAJOR)
-                for (size_t j = 0; j < OtherColumns; ++j)
-                    for (size_t k = 0; k < Columns; ++k)
+                for (std::size_t j = 0; j < OtherColumns; ++j)
+                    for (std::size_t k = 0; k < Columns; ++k)
                     {
                         const Type bkj = other.at(k, j);
-                        for (size_t i = 0; i < Rows; ++i)
+                        for (std::size_t i = 0; i < Rows; ++i)
                             result.at(i, j) += at(i, k) * bkj;
                     }
             else