diff --git a/lib/tx.py b/lib/tx.py
index 8e1878f..79a6360 100644
--- a/lib/tx.py
+++ b/lib/tx.py
@@ -71,7 +71,8 @@ class TxOutput(namedtuple("TxOutput", "value pk_script")):
 class Deserializer(object):
     '''Deserializes blocks into transactions.
 
-    External entry points are read_tx() and read_block().
+    External entry points are read_tx(), read_tx_and_hash(),
+    read_tx_and_vsize() and read_block().
 
     This code is performance sensitive as it is executed 100s of
     millions of times during sync.
@@ -84,25 +85,32 @@ class Deserializer(object):
         self.cursor = start
 
     def read_tx(self):
-        '''Return a (Deserialized TX, TX_HASH) pair.
-
-        The hash needs to be reversed for human display; for efficiency
-        we process it in the natural serialized order.
-        '''
-        start = self.cursor
+        '''Return a deserialized transaction.'''
         return Tx(
             self._read_le_int32(),  # version
             self._read_inputs(),    # inputs
             self._read_outputs(),   # outputs
             self._read_le_uint32()  # locktime
-        ), double_sha256(self.binary[start:self.cursor])
+        )
+
+    def read_tx_and_hash(self):
+        '''Return a (deserialized TX, tx_hash) pair.
+
+        The hash needs to be reversed for human display; for efficiency
+        we process it in the natural serialized order.
+        '''
+        start = self.cursor
+        return self.read_tx(), double_sha256(self.binary[start:self.cursor])
+
+    def read_tx_and_vsize(self):
+        '''Return a (deserialized TX, vsize) pair.'''
+        return self.read_tx(), self.binary_length
 
     def read_tx_block(self):
         '''Returns a list of (deserialized_tx, tx_hash) pairs.'''
-        read_tx = self.read_tx
-        txs = [read_tx() for _ in range(self._read_varint())]
+        read = self.read_tx_and_hash
         # Some coins have excess data beyond the end of the transactions
-        return txs
+        return [read() for _ in range(self._read_varint())]
 
     def _read_inputs(self):
         read_input = self._read_input
@@ -198,15 +206,12 @@ class DeserializerSegWit(Deserializer):
         read_varbytes = self._read_varbytes
         return [read_varbytes() for i in range(self._read_varint())]
 
-    def read_tx(self):
-        '''Return a (Deserialized TX, TX_HASH) pair.
-
-        The hash needs to be reversed for human display; for efficiency
-        we process it in the natural serialized order.
-        '''
+    def _read_tx_parts(self):
+        '''Return a (deserialized TX, tx_hash, vsize) tuple.'''
         marker = self.binary[self.cursor + 4]
         if marker:
-            return super().read_tx()
+            tx, tx_hash = super().read_tx_and_hash()
+            return tx, tx_hash, self.binary_size
 
         # Ugh, this is nasty.
         start = self.cursor
@@ -221,14 +226,27 @@ class DeserializerSegWit(Deserializer):
         outputs = self._read_outputs()
         orig_ser += self.binary[start:self.cursor]
 
+        base_size = self.cursor - start
         witness = self._read_witness(len(inputs))
 
         start = self.cursor
         locktime = self._read_le_uint32()
         orig_ser += self.binary[start:self.cursor]
+        vsize = (3 * base_size + self.binary_length) // 4
+
+        return TxSegWit(version, marker, flag, inputs, outputs, witness,
+                        locktime), double_sha256(orig_ser), vsize
+
+    def read_tx(self):
+        return self._read_tx_parts()[0]
+
+    def read_tx_and_hash(self):
+        tx, tx_hash, vsize = self._read_tx_parts()
+        return tx, tx_hash
 
-        return TxSegWit(version, marker, flag, inputs,
-                        outputs, witness, locktime), double_sha256(orig_ser)
+    def read_tx_and_vsize(self):
+        tx, tx_hash, vsize = self._read_tx_parts()
+        return tx, vsize
 
 
 class DeserializerAuxPow(Deserializer):
@@ -289,7 +307,6 @@ class TxJoinSplit(namedtuple("Tx", "version inputs outputs locktime")):
 
 class DeserializerZcash(DeserializerEquihash):
     def read_tx(self):
-        start = self.cursor
         base_tx =  TxJoinSplit(
             self._read_le_int32(),  # version
             self._read_inputs(),    # inputs
@@ -302,7 +319,7 @@ class DeserializerZcash(DeserializerEquihash):
                 self.cursor += joinsplit_size * 1802 # JSDescription
                 self.cursor += 32 # joinSplitPubKey
                 self.cursor += 64 # joinSplitSig
-        return base_tx, double_sha256(self.binary[start:self.cursor])
+        return base_tx
 
 
 class TxTime(namedtuple("Tx", "version time inputs outputs locktime")):
@@ -315,21 +332,17 @@ class TxTime(namedtuple("Tx", "version time inputs outputs locktime")):
 
 class DeserializerTxTime(Deserializer):
     def read_tx(self):
-        start = self.cursor
-
         return TxTime(
             self._read_le_int32(),  # version
             self._read_le_uint32(), # time
             self._read_inputs(),    # inputs
             self._read_outputs(),   # outputs
             self._read_le_uint32(), # locktime
-        ), double_sha256(self.binary[start:self.cursor])
+        )
 
 
 class DeserializerReddcoin(Deserializer):
     def read_tx(self):
-        start = self.cursor
-
         version = self._read_le_int32()
         inputs = self._read_inputs()
         outputs = self._read_outputs()
@@ -339,13 +352,7 @@ class DeserializerReddcoin(Deserializer):
         else:
             time = 0
 
-        return TxTime(
-            version,
-            time,
-            inputs,
-            outputs,
-            locktime,
-        ), double_sha256(self.binary[start:self.cursor])
+        return TxTime(version, time, inputs, outputs, locktime)
 
 
 class DeserializerTxTimeAuxPow(DeserializerTxTime):
diff --git a/server/controller.py b/server/controller.py
index e0c3428..fecb4b9 100644
--- a/server/controller.py
+++ b/server/controller.py
@@ -873,7 +873,7 @@ class Controller(ServerBase):
         if not raw_tx:
             return None
         raw_tx = util.hex_to_bytes(raw_tx)
-        tx, tx_hash = self.coin.DESERIALIZER(raw_tx).read_tx()
+        tx = self.coin.DESERIALIZER(raw_tx).read_tx()
         if index >= len(tx.outputs):
             return None
         return self.coin.address_from_script(tx.outputs[index].pk_script)
diff --git a/server/mempool.py b/server/mempool.py
index c5e35d3..219a38c 100644
--- a/server/mempool.py
+++ b/server/mempool.py
@@ -217,7 +217,7 @@ class MemPool(util.LoggedClass):
         for tx_hash, raw_tx in raw_tx_map.items():
             if tx_hash not in txs:
                 continue
-            tx, _tx_hash = deserializer(raw_tx).read_tx()
+            tx = deserializer(raw_tx).read_tx()
 
             # Convert the tx outputs into (hashX, value) pairs
             txout_pairs = [(script_hashX(txout.pk_script), txout.value)
@@ -301,7 +301,7 @@ class MemPool(util.LoggedClass):
             txin_pairs, txout_pairs = item
             tx_fee = (sum(v for hashX, v in txin_pairs) -
                       sum(v for hashX, v in txout_pairs))
-            tx, tx_hash = deserializer(raw_tx).read_tx()
+            tx = deserializer(raw_tx).read_tx()
             unconfirmed = any(hash_to_str(txin.prev_hash) in self.txs
                               for txin in tx.inputs)
             result.append((hex_hash, tx_fee, unconfirmed))
@@ -319,7 +319,7 @@ class MemPool(util.LoggedClass):
         for hex_hash, raw_tx in pairs:
             if not raw_tx:
                 continue
-            tx, tx_hash = deserializer(raw_tx).read_tx()
+            tx = deserializer(raw_tx).read_tx()
             for txin in tx.inputs:
                 spends.add((txin.prev_hash, txin.prev_idx))
         return spends