diff --git a/src/arith_uint256.h b/src/arith_uint256.h
index 0ee4cf9622d8d0..89a5272f1f9f8f 100644
--- a/src/arith_uint256.h
+++ b/src/arith_uint256.h
@@ -25,7 +25,7 @@ template<unsigned int BITS>
 class base_uint
 {
 protected:
-    enum { WIDTH=BITS/32 };
+    static constexpr int WIDTH = BITS / 32;
     uint32_t pn[WIDTH];
 public:
 
diff --git a/src/chain.h b/src/chain.h
index f29580e7fbdc5c..4e3bbbad2d7bed 100644
--- a/src/chain.h
+++ b/src/chain.h
@@ -304,7 +304,7 @@ class CBlockIndex
         return (int64_t)nTimeMax;
     }
 
-    enum { nMedianTimeSpan=11 };
+    static constexpr int nMedianTimeSpan = 11;
 
     int64_t GetMedianTimePast() const
     {
diff --git a/src/consensus/consensus.h b/src/consensus/consensus.h
index 0efe580c1e0827..cd631168f3cb2b 100644
--- a/src/consensus/consensus.h
+++ b/src/consensus/consensus.h
@@ -24,12 +24,9 @@ static const unsigned int MAX_TX_EXTRA_PAYLOAD = 10000;
 static const int COINBASE_MATURITY = 100;
 
 /** Flags for nSequence and nLockTime locks */
-enum {
-    /* Interpret sequence numbers as relative lock-time constraints. */
-    LOCKTIME_VERIFY_SEQUENCE = (1 << 0),
-
-    /* Use GetMedianTimePast() instead of nTime for end point timestamp. */
-    LOCKTIME_MEDIAN_TIME_PAST = (1 << 1),
-};
+/** Interpret sequence numbers as relative lock-time constraints. */
+static constexpr unsigned int LOCKTIME_VERIFY_SEQUENCE = (1 << 0);
+/** Use GetMedianTimePast() instead of nTime for end point timestamp. */
+static constexpr unsigned int LOCKTIME_MEDIAN_TIME_PAST = (1 << 1);
 
 #endif // BITCOIN_CONSENSUS_CONSENSUS_H
diff --git a/src/protocol.h b/src/protocol.h
index 4bf0cdf00a69ff..25a3cc708fdab0 100644
--- a/src/protocol.h
+++ b/src/protocol.h
@@ -27,16 +27,13 @@
 class CMessageHeader
 {
 public:
-    enum {
-        MESSAGE_START_SIZE = 4,
-        COMMAND_SIZE = 12,
-        MESSAGE_SIZE_SIZE = 4,
-        CHECKSUM_SIZE = 4,
-
-        MESSAGE_SIZE_OFFSET = MESSAGE_START_SIZE + COMMAND_SIZE,
-        CHECKSUM_OFFSET = MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE,
-        HEADER_SIZE = MESSAGE_START_SIZE + COMMAND_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE
-    };
+    static constexpr size_t MESSAGE_START_SIZE = 4;
+    static constexpr size_t COMMAND_SIZE = 12;
+    static constexpr size_t MESSAGE_SIZE_SIZE = 4;
+    static constexpr size_t CHECKSUM_SIZE = 4;
+    static constexpr size_t MESSAGE_SIZE_OFFSET = MESSAGE_START_SIZE + COMMAND_SIZE;
+    static constexpr size_t CHECKSUM_OFFSET = MESSAGE_SIZE_OFFSET + MESSAGE_SIZE_SIZE;
+    static constexpr size_t HEADER_SIZE = MESSAGE_START_SIZE + COMMAND_SIZE + MESSAGE_SIZE_SIZE + CHECKSUM_SIZE;
     typedef unsigned char MessageStartChars[MESSAGE_START_SIZE];
 
     explicit CMessageHeader(const MessageStartChars& pchMessageStartIn);
diff --git a/src/uint256.h b/src/uint256.h
index a1ad3db129005b..9d74c292a31c73 100644
--- a/src/uint256.h
+++ b/src/uint256.h
@@ -20,7 +20,7 @@ template<unsigned int BITS>
 class base_blob
 {
 protected:
-    enum { WIDTH=BITS/8 };
+    static constexpr int WIDTH = BITS / 8;
     uint8_t data[WIDTH];
 public:
     base_blob()