diff --git a/src/bitcoinrpc.cpp b/src/bitcoinrpc.cpp
index 960ce6ccd..1372548b7 100644
--- a/src/bitcoinrpc.cpp
+++ b/src/bitcoinrpc.cpp
@@ -1144,6 +1144,7 @@ Array RPCConvertValues(const std::string &strMethod, const std::vector<std::stri
     if (strMethod == "stop"                   && n > 0) ConvertTo<bool>(params[0]);
     if (strMethod == "getaddednodeinfo"       && n > 0) ConvertTo<bool>(params[0]);
     if (strMethod == "getnetworkhashps"       && n > 0) ConvertTo<boost::int64_t>(params[0]);
+    if (strMethod == "getnetworkhashps"       && n > 1) ConvertTo<boost::int64_t>(params[1]);
     if (strMethod == "sendtoaddress"          && n > 1) ConvertTo<double>(params[1]);
     if (strMethod == "settxfee"               && n > 0) ConvertTo<double>(params[0]);
     if (strMethod == "setmininput"            && n > 0) ConvertTo<double>(params[0]);
diff --git a/src/rpcmining.cpp b/src/rpcmining.cpp
index 000b52b04..fb722776a 100644
--- a/src/rpcmining.cpp
+++ b/src/rpcmining.cpp
@@ -12,24 +12,28 @@ using namespace json_spirit;
 using namespace std;
 
 // Litecoin: Return average network hashes per second based on last number of blocks.
-Value GetNetworkHashPS(int lookup) {
-    if (pindexBest == NULL)
+Value GetNetworkHashPS(int lookup, int height) {
+    CBlockIndex *pb = pindexBest;
+
+    if (height >= 0 && height < nBestHeight)
+        pb = FindBlockByHeight(height);
+
+    if (pb == NULL || !pb->nHeight)
         return 0;
 
     // If lookup is -1, then use blocks since last difficulty change.
     if (lookup <= 0)
-        lookup = pindexBest->nHeight % 2016 + 1;
+        lookup = pb->nHeight % 2016 + 1;
 
     // If lookup is larger than chain, then set it to chain length.
-    if (lookup > pindexBest->nHeight)
-        lookup = pindexBest->nHeight;
+    if (lookup > pb->nHeight)
+        lookup = pb->nHeight;
 
-    CBlockIndex* pindexPrev = pindexBest;
     double sum = 0.0;
     for (int i = 0; i < lookup; i++)
     {
-        sum += (pindexPrev->GetBlockTime() - pindexPrev->pprev->GetBlockTime()) / GetDifficulty(pindexPrev);
-        pindexPrev = pindexPrev->pprev;
+        sum += (pb->GetBlockTime() - pb->pprev->GetBlockTime()) / GetDifficulty(pb);
+        pb = pb->pprev;
     }
 
     return (boost::int64_t)(pow(2.0, 32) / (sum / lookup));
@@ -37,13 +41,14 @@ Value GetNetworkHashPS(int lookup) {
 
 Value getnetworkhashps(const Array& params, bool fHelp)
 {
-    if (fHelp || params.size() > 1)
+    if (fHelp || params.size() > 2)
         throw runtime_error(
-            "getnetworkhashps [blocks]\n"
+            "getnetworkhashps [blocks] [height]\n"
             "Returns the estimated network hashes per second based on the last 120 blocks.\n"
-            "Pass in [blocks] to override # of blocks, -1 specifies since last difficulty change.");
+            "Pass in [blocks] to override # of blocks, -1 specifies since last difficulty change.\n"
+            "Pass in [height] to estimate the network speed at the time when a certain block was found.");
 
-    return GetNetworkHashPS(params.size() > 0 ? params[0].get_int() : 120);
+    return GetNetworkHashPS(params.size() > 0 ? params[0].get_int() : 120, params.size() > 1 ? params[1].get_int() : -1);
 }
 
 Value getmininginfo(const Array& params, bool fHelp)