diff --git a/src/coins.cpp b/src/coins.cpp
index f0ea5c045..723e11470 100644
--- a/src/coins.cpp
+++ b/src/coins.cpp
@@ -243,8 +243,9 @@ bool CCoinsViewCache::HaveInputs(const CTransaction& tx) const
     return true;
 }
 
-double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight) const
+double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight, CAmount &inChainInputValue) const
 {
+    inChainInputValue = 0;
     if (tx.IsCoinBase())
         return 0.0;
     double dResult = 0.0;
@@ -253,8 +254,9 @@ double CCoinsViewCache::GetPriority(const CTransaction &tx, int nHeight) const
         const CCoins* coins = AccessCoins(txin.prevout.hash);
         assert(coins);
         if (!coins->IsAvailable(txin.prevout.n)) continue;
-        if (coins->nHeight < nHeight) {
+        if (coins->nHeight <= nHeight) {
             dResult += coins->vout[txin.prevout.n].nValue * (nHeight-coins->nHeight);
+            inChainInputValue += coins->vout[txin.prevout.n].nValue;
         }
     }
     return tx.ComputePriority(dResult);
diff --git a/src/coins.h b/src/coins.h
index 99b25de45..d17442210 100644
--- a/src/coins.h
+++ b/src/coins.h
@@ -456,8 +456,12 @@ public:
     //! Check whether all prevouts of the transaction are present in the UTXO set represented by this view
     bool HaveInputs(const CTransaction& tx) const;
 
-    //! Return priority of tx at height nHeight
-    double GetPriority(const CTransaction &tx, int nHeight) const;
+    /**
+     * Return priority of tx at height nHeight. Also calculate the sum of the values of the inputs
+     * that are already in the chain.  These are the inputs that will age and increase priority as
+     * new blocks are added to the chain.
+     */
+    double GetPriority(const CTransaction &tx, int nHeight, CAmount &inChainInputValue) const;
 
     const CTxOut &GetOutputFor(const CTxIn& input) const;
 
diff --git a/src/main.cpp b/src/main.cpp
index 33bd2e0ce..55b051734 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -950,9 +950,10 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
 
         CAmount nValueOut = tx.GetValueOut();
         CAmount nFees = nValueIn-nValueOut;
-        double dPriority = view.GetPriority(tx, chainActive.Height());
+        CAmount inChainInputValue;
+        double dPriority = view.GetPriority(tx, chainActive.Height(), inChainInputValue);
 
-        CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx));
+        CTxMemPoolEntry entry(tx, nFees, GetTime(), dPriority, chainActive.Height(), pool.HasNoInputsOf(tx), inChainInputValue);
         unsigned int nSize = entry.GetTxSize();
 
         // Don't accept it if it can't get into a block
@@ -964,7 +965,7 @@ bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransa
         CAmount mempoolRejectFee = pool.GetMinFee(GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000).GetFee(nSize);
         if (mempoolRejectFee > 0 && nFees < mempoolRejectFee) {
             return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "mempool min fee not met", false, strprintf("%d < %d", nFees, mempoolRejectFee));
-        } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY) && nFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(view.GetPriority(tx, chainActive.Height() + 1))) {
+        } else if (GetBoolArg("-relaypriority", DEFAULT_RELAYPRIORITY) && nFees < ::minRelayTxFee.GetFee(nSize) && !AllowFree(entry.GetPriority(chainActive.Height() + 1))) {
             // Require that free transactions have sufficient priority to be mined in the next block.
             return state.DoS(0, false, REJECT_INSUFFICIENTFEE, "insufficient priority");
         }
diff --git a/src/test/policyestimator_tests.cpp b/src/test/policyestimator_tests.cpp
index 1315146f1..644c3da21 100644
--- a/src/test/policyestimator_tests.cpp
+++ b/src/test/policyestimator_tests.cpp
@@ -196,7 +196,7 @@ BOOST_AUTO_TEST_CASE(BlockPolicyEstimates)
 
     // Test that if the mempool is limited, estimateSmartFee won't return a value below the mempool min fee
     // and that estimateSmartPriority returns essentially an infinite value
-    mpool.addUnchecked(tx.GetHash(),  CTxMemPoolEntry(tx, feeV[0][5], GetTime(), priV[1][5], blocknum, mpool.HasNoInputsOf(tx)));
+    mpool.addUnchecked(tx.GetHash(),  entry.Fee(feeV[0][5]).Time(GetTime()).Priority(priV[1][5]).Height(blocknum).FromTx(tx, &mpool));
     // evict that transaction which should set a mempool min fee of minRelayTxFee + feeV[0][5]
     mpool.TrimToSize(1);
     BOOST_CHECK(mpool.GetMinFee(1).GetFeePerK() > feeV[0][5]);
diff --git a/src/test/test_bitcoin.cpp b/src/test/test_bitcoin.cpp
index 2fe190f88..351870014 100644
--- a/src/test/test_bitcoin.cpp
+++ b/src/test/test_bitcoin.cpp
@@ -144,8 +144,13 @@ TestChain100Setup::~TestChain100Setup()
 
 
 CTxMemPoolEntry TestMemPoolEntryHelper::FromTx(CMutableTransaction &tx, CTxMemPool *pool) {
-    return CTxMemPoolEntry(tx, nFee, nTime, dPriority, nHeight,
-                           pool ? pool->HasNoInputsOf(tx) : hadNoDependencies);
+    CTransaction txn(tx);
+    bool hasNoDependencies = pool ? pool->HasNoInputsOf(tx) : hadNoDependencies;
+    // Hack to assume either its completely dependent on other mempool txs or not at all
+    CAmount inChainValue = hasNoDependencies ? txn.GetValueOut() : 0;
+
+    return CTxMemPoolEntry(txn, nFee, nTime, dPriority, nHeight,
+                           hasNoDependencies, inChainValue);
 }
 
 void Shutdown(void* parg)
diff --git a/src/txmempool.cpp b/src/txmempool.cpp
index ec7971c2f..6d1df0b3d 100644
--- a/src/txmempool.cpp
+++ b/src/txmempool.cpp
@@ -19,10 +19,10 @@
 using namespace std;
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTransaction& _tx, const CAmount& _nFee,
-                                 int64_t _nTime, double _dPriority,
-                                 unsigned int _nHeight, bool poolHasNoInputsOf):
-    tx(_tx), nFee(_nFee), nTime(_nTime), dPriority(_dPriority), nHeight(_nHeight),
-    hadNoDependencies(poolHasNoInputsOf)
+                                 int64_t _nTime, double _entryPriority, unsigned int _entryHeight,
+                                 bool poolHasNoInputsOf, CAmount _inChainInputValue):
+    tx(_tx), nFee(_nFee), nTime(_nTime), entryPriority(_entryPriority), entryHeight(_entryHeight),
+    hadNoDependencies(poolHasNoInputsOf), inChainInputValue(_inChainInputValue)
 {
     nTxSize = ::GetSerializeSize(tx, SER_NETWORK, PROTOCOL_VERSION);
     nModSize = tx.CalculateModifiedSize(nTxSize);
@@ -31,6 +31,8 @@ CTxMemPoolEntry::CTxMemPoolEntry(const CTransaction& _tx, const CAmount& _nFee,
     nCountWithDescendants = 1;
     nSizeWithDescendants = nTxSize;
     nFeesWithDescendants = nFee;
+    CAmount nValueIn = tx.GetValueOut()+nFee;
+    assert(inChainInputValue <= nValueIn);
 }
 
 CTxMemPoolEntry::CTxMemPoolEntry(const CTxMemPoolEntry& other)
@@ -41,9 +43,10 @@ CTxMemPoolEntry::CTxMemPoolEntry(const CTxMemPoolEntry& other)
 double
 CTxMemPoolEntry::GetPriority(unsigned int currentHeight) const
 {
-    CAmount nValueIn = tx.GetValueOut()+nFee;
-    double deltaPriority = ((double)(currentHeight-nHeight)*nValueIn)/nModSize;
-    double dResult = dPriority + deltaPriority;
+    double deltaPriority = ((double)(currentHeight-entryHeight)*inChainInputValue)/nModSize;
+    double dResult = entryPriority + deltaPriority;
+    if (dResult < 0) // This should only happen if it was called with a height below entry height
+        dResult = 0;
     return dResult;
 }
 
diff --git a/src/txmempool.h b/src/txmempool.h
index 7f43120f7..c470bbe28 100644
--- a/src/txmempool.h
+++ b/src/txmempool.h
@@ -63,9 +63,10 @@ private:
     size_t nModSize; //! ... and modified size for priority
     size_t nUsageSize; //! ... and total memory usage
     int64_t nTime; //! Local time when entering the mempool
-    double dPriority; //! Priority when entering the mempool
-    unsigned int nHeight; //! Chain height when entering the mempool
+    double entryPriority; //! Priority when entering the mempool
+    unsigned int entryHeight; //! Chain height when entering the mempool
     bool hadNoDependencies; //! Not dependent on any other txs when it entered the mempool
+    CAmount inChainInputValue; //! Sum of all txin values that are already in blockchain
 
     // Information about descendants of this transaction that are in the
     // mempool; if we remove this transaction we must remove all of these
@@ -78,15 +79,20 @@ private:
 
 public:
     CTxMemPoolEntry(const CTransaction& _tx, const CAmount& _nFee,
-                    int64_t _nTime, double _dPriority, unsigned int _nHeight, bool poolHasNoInputsOf = false);
+                    int64_t _nTime, double _entryPriority, unsigned int _entryHeight,
+                    bool poolHasNoInputsOf, CAmount _inChainInputValue);
     CTxMemPoolEntry(const CTxMemPoolEntry& other);
 
     const CTransaction& GetTx() const { return this->tx; }
+    /**
+     * Fast calculation of lower bound of current priority as update
+     * from entry priority. Only inputs that were originally in-chain will age.
+     */
     double GetPriority(unsigned int currentHeight) const;
     const CAmount& GetFee() const { return nFee; }
     size_t GetTxSize() const { return nTxSize; }
     int64_t GetTime() const { return nTime; }
-    unsigned int GetHeight() const { return nHeight; }
+    unsigned int GetHeight() const { return entryHeight; }
     bool WasClearAtEntry() const { return hadNoDependencies; }
     size_t DynamicMemoryUsage() const { return nUsageSize; }