diff --git a/src/checkpoints.cpp b/src/checkpoints.cpp
index 7fd94e4e7..026475f88 100644
--- a/src/checkpoints.cpp
+++ b/src/checkpoints.cpp
@@ -74,7 +74,7 @@ namespace Checkpoints {
             fWorkAfter = nExpensiveAfter*fSigcheckVerificationFactor;
         }
 
-        return fWorkBefore / (fWorkBefore + fWorkAfter);
+        return std::min(fWorkBefore / (fWorkBefore + fWorkAfter), 1.0);
     }
 
     int GetTotalBlocksEstimate(const CChainParams::CCheckpointData& data)