diff --git a/src/kaleidoscope/MatrixAddr.h b/src/kaleidoscope/MatrixAddr.h
index a7a5cbbf..8e13ddbe 100644
--- a/src/kaleidoscope/MatrixAddr.h
+++ b/src/kaleidoscope/MatrixAddr.h
@@ -47,7 +47,7 @@ class MatrixAddr {
   constexpr MatrixAddr(uint8_t row, uint8_t col)
     : offset_(row * cols + col) {}
 
-  constexpr MatrixAddr(uint8_t offset)
+  explicit constexpr MatrixAddr(uint8_t offset)
     : offset_(offset) {}
 
   // Rely on the default copy and move constructor.
diff --git a/src/kaleidoscope/bitfields.h b/src/kaleidoscope/bitfields.h
index 3a59c854..52621143 100644
--- a/src/kaleidoscope/bitfields.h
+++ b/src/kaleidoscope/bitfields.h
@@ -113,7 +113,7 @@ class Bitfield : public internal::_BaseBitfield {
   static constexpr size_t n_bytes_ = nBytesForBits(BitCount__);
 
   template<typename ... Bits__>
-  constexpr Bitfield(Bits__...bits) : bits_(bits...) {
+  explicit constexpr Bitfield(Bits__...bits) : bits_(bits...) {
     static_assert(sizeof...(Bits__) == n_bits_,
                   "Invalid number of bits supplied to Bitfield<BitCount__> constructor. \n"
                   "Compare the number of bits supplied with the provided template \n"