diff --git a/src/feerate.h b/src/feerate.h
--- a/src/feerate.h
+++ b/src/feerate.h
@@ -84,6 +84,9 @@
         nSatoshisPerK += a.nSatoshisPerK;
         return *this;
     }
+    CFeeRate operator+(const CFeeRate &a) {
+        return CFeeRate(nSatoshisPerK + a.nSatoshisPerK);
+    }
     std::string ToString() const;
 
     ADD_SERIALIZE_METHODS;
diff --git a/src/policy/fees.h b/src/policy/fees.h
--- a/src/policy/fees.h
+++ b/src/policy/fees.h
@@ -14,6 +14,37 @@
 #include <vector>
 
 class CFeeRate;
+class CTxMemPoolEntry;
+class CTxMemPool;
+
+/** \class MempoolFeeEstimator
+ * The MempoolFeeEstimator is used for estimating the feerate needed for a
+ * transaction to be included in a block within a certain number of blocks.
+ */
+class MempoolFeeEstimator {
+private:
+    std::vector<CFeeRate> m_minHeap;
+    std::vector<CFeeRate> m_maxHeap;
+
+public:
+    MempoolFeeEstimator() {}
+
+    /**
+     * Clear the state of the curBlock variables to start counting for after a
+     * block is received.
+     */
+    void clear();
+
+    /**
+     * Record a new fee data point in the current block stats
+     */
+    void addFee(CFeeRate fee);
+
+    /**
+     * Calculate a feerate estimate.
+     */
+    CFeeRate estimateMedian();
+};
 
 // Minimum and Maximum values for tracking feerates
 static constexpr Amount MIN_FEERATE(10 * SATOSHI);
diff --git a/src/policy/fees.cpp b/src/policy/fees.cpp
--- a/src/policy/fees.cpp
+++ b/src/policy/fees.cpp
@@ -8,6 +8,51 @@
 
 #include "amount.h"
 #include "feerate.h"
+#include "primitives/transaction.h"
+#include "random.h"
+#include "streams.h"
+#include "txmempool.h"
+#include "util.h"
+
+#include <iostream>
+
+void MempoolFeeEstimator::clear() {
+    m_maxHeap.resize(0);
+    m_minHeap.resize(0);
+}
+
+static bool minComparor(const CFeeRate &a, const CFeeRate &b) {
+    return a < b;
+}
+
+void MempoolFeeEstimator::addFee(CFeeRate fee) {
+    auto maxHeapSize = m_maxHeap.size();
+    auto minHeapSize = m_minHeap.size();
+
+    if (maxHeapSize == 0 || fee <= m_maxHeap.front()) {
+        m_maxHeap.push_back(fee);
+        std::push_heap(m_maxHeap.begin(), m_maxHeap.end());
+    } else if (minHeapSize == 0 || fee <= m_minHeap.front()) {
+        m_minHeap.push_back(fee);
+        std::push_heap(m_minHeap.begin(), m_minHeap.end(), minComparor);
+    } else if (maxHeapSize < minHeapSize) {
+        m_maxHeap.push_back(fee);
+        std::push_heap(m_maxHeap.begin(), m_maxHeap.end(), minComparor);
+    } else {
+        m_minHeap.push_back(fee);
+        std::push_heap(m_minHeap.begin(), m_minHeap.end(), minComparor);
+    }
+}
+
+CFeeRate MempoolFeeEstimator::estimateMedian() {
+    if (m_maxHeap.size() == m_minHeap.size()) {
+        return CFeeRate(
+            (m_minHeap.front().GetFeePerK() + m_maxHeap.front().GetFeePerK()) /
+            2);
+    }
+    std::cout << "interesting" << std::endl;
+    return m_maxHeap.front();
+}
 
 FeeFilterRounder::FeeFilterRounder(const CFeeRate &minIncrementalFee) {
     Amount minFeeLimit = std::max(SATOSHI, minIncrementalFee.GetFeePerK() / 2);
diff --git a/src/test/policyestimator_tests.cpp b/src/test/policyestimator_tests.cpp
--- a/src/test/policyestimator_tests.cpp
+++ b/src/test/policyestimator_tests.cpp
@@ -14,6 +14,25 @@
 
 BOOST_FIXTURE_TEST_SUITE(policyestimator_tests, BasicTestingSetup)
 
+BOOST_AUTO_TEST_CASE(test_MempoolFeeEstimator) {
+    MempoolFeeEstimator estimator;
+    estimator.addFee(CFeeRate(5 * SATOSHI));
+    estimator.addFee(CFeeRate(4 * SATOSHI));
+    estimator.addFee(CFeeRate(1 * SATOSHI));
+    estimator.addFee(CFeeRate(2 * SATOSHI));
+    estimator.addFee(CFeeRate(3 * SATOSHI));
+    BOOST_CHECK_MESSAGE(
+        estimator.estimateMedian() == CFeeRate(3 * SATOSHI),
+        "Median is incorrect: " << estimator.estimateMedian().ToString());
+    estimator.addFee(CFeeRate(4 * SATOSHI));
+    estimator.addFee(CFeeRate(5 * SATOSHI));
+    estimator.addFee(CFeeRate(3 * SATOSHI));
+    estimator.addFee(CFeeRate(3 * SATOSHI));
+    BOOST_CHECK_MESSAGE(
+        estimator.estimateMedian() == CFeeRate(3 * SATOSHI),
+        "Median is incorrect: " << estimator.estimateMedian().ToString());
+}
+
 BOOST_AUTO_TEST_CASE(MempoolMinimumFeeEstimate) {
     CTxMemPool mpool;
     TestMemPoolEntryHelper entry;
diff --git a/src/wallet/fees.h b/src/wallet/fees.h
--- a/src/wallet/fees.h
+++ b/src/wallet/fees.h
@@ -9,7 +9,6 @@
 
 #include "amount.h"
 
-class CBlockPolicyEstimator;
 class CCoinControl;
 class CFeeRate;
 class CTxMemPool;