diff --git a/src/crypto/sha512.h b/src/crypto/sha512.h
--- a/src/crypto/sha512.h
+++ b/src/crypto/sha512.h
@@ -22,6 +22,7 @@
     CSHA512 &Write(const uint8_t *data, size_t len);
     void Finalize(uint8_t hash[OUTPUT_SIZE]);
     CSHA512 &Reset();
+    uint64_t Size() const { return bytes; }
 };
 
 #endif // BITCOIN_CRYPTO_SHA512_H
diff --git a/src/random.cpp b/src/random.cpp
--- a/src/random.cpp
+++ b/src/random.cpp
@@ -576,7 +576,10 @@
     SeedTimestamp(hasher);
 
     // Dynamic environment data (performance monitoring, ...)
+    auto old_size = hasher.Size();
     RandAddDynamicEnv(hasher);
+    LogPrintf("Feeding %i bytes of dynamic environment data into RNG\n",
+              hasher.Size() - old_size);
 
     // Strengthen for 10ms
     SeedStrengthen(hasher, rng, 10000);
@@ -590,10 +593,13 @@
     SeedSlow(hasher);
 
     // Dynamic environment data (performance monitoring, ...)
+    auto old_size = hasher.Size();
     RandAddDynamicEnv(hasher);
 
     // Static environment data
     RandAddStaticEnv(hasher);
+    LogPrintf("Feeding %i bytes of environment data into RNG\n",
+              hasher.Size() - old_size);
 
     // Strengthen for 100ms
     SeedStrengthen(hasher, rng, 100000);