diff --git a/src/main.go b/src/main.go
index f4ea1ce..f8ea35d 100644
--- a/src/main.go
+++ b/src/main.go
@@ -6,13 +6,18 @@ import (
 	"github.com/humblenginr/btc-miner/mining"
 	txn "github.com/humblenginr/btc-miner/transaction"
 	"github.com/humblenginr/btc-miner/utils"
+	"github.com/humblenginr/btc-miner/txnpicker"
 )
 
 
-var OutputFilePath = "../output.txt"
-
-
+var (
+    OutputFilePath = "../output.txt"
+    MempoolDirPath = "../mempool"
+    MaxTxWeight = 4000000
+    BlockHeaderWeight = 320
+    MaxTotalWeight = 4000000 - BlockHeaderWeight
 
+)
 
 func LogDetailsAboutTx(tx txn.Transaction){
     txid := tx.TxHash()
@@ -23,7 +28,8 @@ func LogDetailsAboutTx(tx txn.Transaction){
 }
 
 func main() {
-    pq := GetTxnsQ()
-    candidateBlock := mining.GetCandidateBlock(pq, true)
+    picker := txnpicker.NewTransactionPicker(MempoolDirPath, MaxTxWeight, MaxTotalWeight)
+    txns := picker.PickUsingPQ()
+    candidateBlock := mining.GetCandidateBlock(txns, true)
     mining.MineBlock(candidateBlock, OutputFilePath)
 }
diff --git a/src/transaction/tx.go b/src/transaction/tx.go
index 968d0f9..cb0eba4 100644
--- a/src/transaction/tx.go
+++ b/src/transaction/tx.go
@@ -119,22 +119,8 @@ func (t *Transaction) HasWitness() bool {
 	return false
 }
 
-
-func (tx *Transaction) SerializeSizeWithWitness() int {
-    witnessSize := 0
-    for _, t := range tx.Vin {
-        witnessByteArray := make([][]byte, 0)
-        for _, w := range t.Witness{
-            witness,_ := hex.DecodeString(w)
-            witnessByteArray = append(witnessByteArray, witness)
-        }
-        witnessSize += SerializeWitnessSize(witnessByteArray)
-    }
-    return tx.SerializeSize() + witnessSize
-}
-
 // SerializeSize returns the serialized size of the transaction without accounting for any witness data.
-func (tx *Transaction) SerializeSize() int {
+func (tx *Transaction) SerializeSize(witness bool) int {
 	// Version 4 bytes + LockTime 4 bytes + Serialized varint size for the
 	// number of transaction inputs and outputs.
 	n := 8 + VarIntSerializeSize(uint64(len(tx.Vin))) +
@@ -148,7 +134,7 @@ func (tx *Transaction) SerializeSize() int {
 		n += txOut.SerializeSize()
 	}
 
-	if tx.HasWitness() {
+	if tx.HasWitness() && witness {
 		// The marker, and flag fields take up two additional bytes.
 		n += 2
 
@@ -176,25 +162,9 @@ func (t Transaction) getFeeByWeight() float64 {
 }
 
 func (t Transaction) GetWeight() int {
-    weight := 0 
-    weight += 16
-    weight += 1
-    weight += 1
-    for _, i := range t.Vin {
-        weight += i.SerializeSize() * 4
-
-        witness := make([][]byte, 0)
-        for _, w := range i.Witness {
-            wt,_ := hex.DecodeString(w)
-            witness = append(witness, wt)
-        }
-        weight += SerializeWitnessSize(witness)
-    }
-    for _, o := range t.Vout {
-        weight += o.SerializeSize() * 4
-    }
-    weight += 16
-    return weight
+    nonWitnessSize := t.SerializeSize(false)
+    witnessSize := t.SerializeSize(true) - nonWitnessSize
+    return nonWitnessSize*4 + witnessSize
 }
 
 func (t Transaction) GetFees() int {
@@ -217,7 +187,7 @@ func (t Transaction) String() string {
 
 // RawHex gives the serialized transaction with witness data if any in bytes
 func (t Transaction) RawHex() []byte {
-   w := bytes.NewBuffer(make([]byte, 0, t.SerializeSize()))
+   w := bytes.NewBuffer(make([]byte, 0, t.SerializeSize(true)))
    err := t.Serialize(true, w)
    if err != nil {
       panic(err)
@@ -227,7 +197,7 @@ func (t Transaction) RawHex() []byte {
 }
 
 func (t Transaction) TxHash() []byte {
-    w := bytes.NewBuffer(make([]byte, 0, t.SerializeSize()))
+    w := bytes.NewBuffer(make([]byte, 0, t.SerializeSize(false)))
     // For calculating txid, we don't need the witness data
     err := t.Serialize(false, w)
    if err != nil {
@@ -239,7 +209,7 @@ func (t Transaction) TxHash() []byte {
 }
 
 func (t Transaction) WitnessHash() []byte {
-    w := bytes.NewBuffer(make([]byte, 0, t.SerializeSize()))
+    w := bytes.NewBuffer(make([]byte, 0, t.SerializeSize(true)))
     // For calculating txid, we don't need the witness data
     err := t.Serialize(true, w)
    if err != nil {
diff --git a/src/txnpicker/picker.go b/src/txnpicker/picker.go
index 11d8655..e1c2213 100644
--- a/src/txnpicker/picker.go
+++ b/src/txnpicker/picker.go
@@ -1,7 +1,10 @@
 package txnpicker
 
 import (
+	"fmt"
+
 	txn "github.com/humblenginr/btc-miner/transaction"
+	"github.com/humblenginr/btc-miner/utils"
 )
 
 type TransactionsPicker struct {
@@ -16,7 +19,23 @@ func NewTransactionPicker(mempoolDirPath string, maxTxWeight int, maxTotalWeight
 
 
 // PickTransactionsUsingPQ picks valid transactions from the mempool using priority queue. Transaction with higher fee/weight ratio is considered to be high priority. 
-func (tp *TransactionsPicker) PickTransactionsUsingPQ() []txn.Transaction {
+func (tp *TransactionsPicker) PickUsingPQ() []*txn.Transaction {
     q := getTxnsQ(tp.MempoolDirPath)
+    txns := make([]*txn.Transaction, 0)
+    totalWeight := 0
+
+    item := q.Pop(); 
+    for item != nil {
+        tx := txn.Transaction(item.(Item))
+        weight := tx.GetWeight()
+        fmt.Printf("Weight of the transaction: %d\n", weight)
+        fmt.Printf("Txid: %x\n", utils.ReverseBytes(tx.TxHash()))
+        if(weight+ totalWeight < tp.MaxTotalWeight) {
+            txns = append(txns, &tx)
+            totalWeight += weight
+        }
+        item = q.Pop()
+    }
+    return txns
 }
 
diff --git a/src/validation/sighash/sighash.go b/src/validation/sighash/sighash.go
index 622e86f..1a96396 100644
--- a/src/validation/sighash/sighash.go
+++ b/src/validation/sighash/sighash.go
@@ -91,7 +91,7 @@ func CalcSignatureHash(sigScript []byte, hashType SigHashType, tx *transaction.T
 
 	// double sha256 of the modified serialized
 	// transaction with hash type appended.
-	wbuf := bytes.NewBuffer(make([]byte, 0, txCopy.SerializeSize()+4))
+	wbuf := bytes.NewBuffer(make([]byte, 0, txCopy.SerializeSize(false)+4))
 	txCopy.Serialize(false, wbuf)
 	binary.Write(wbuf, binary.LittleEndian, hashType)
 	return utils.DoubleHash(wbuf.Bytes())