diff --git a/src/cryptonote_core/cryptonote_core.cpp b/src/cryptonote_core/cryptonote_core.cpp
index 9a44d9d3f..a82d96416 100644
--- a/src/cryptonote_core/cryptonote_core.cpp
+++ b/src/cryptonote_core/cryptonote_core.cpp
@@ -616,7 +616,7 @@ namespace cryptonote
     return true;
   }
   //-----------------------------------------------------------------------------------------------
-  std::pair<uint64_t, uint64_t> core::get_coinbase_tx_sum(const uint64_t start_offset, const uint64_t count)
+  std::pair<uint64_t, uint64_t> core::get_coinbase_tx_sum(const uint64_t start_offset, const size_t count)
   {
     std::list<block> blocks;
     std::list<transaction> txs;
diff --git a/src/cryptonote_core/cryptonote_core.h b/src/cryptonote_core/cryptonote_core.h
index 407e89197..d925a184d 100644
--- a/src/cryptonote_core/cryptonote_core.h
+++ b/src/cryptonote_core/cryptonote_core.h
@@ -605,7 +605,7 @@ namespace cryptonote
       *
       * @return the number of blocks to sync in one go
       */
-     std::pair<uint64_t, uint64_t> get_coinbase_tx_sum(const uint64_t start_offset, const uint64_t count);
+     std::pair<uint64_t, uint64_t> get_coinbase_tx_sum(const uint64_t start_offset, const size_t count);
 
    private: