diff --git a/future/transaction.go b/future/transaction.go
index 11697c6c..642a4f66 100644
--- a/future/transaction.go
+++ b/future/transaction.go
@@ -1,9 +1,12 @@
 package future
 
 import (
+	"bytes"
 	"encoding/base64"
 	"fmt"
 
+	"github.com/algorand/go-algorand-sdk/crypto"
+	"github.com/algorand/go-algorand-sdk/encoding/msgpack"
 	"github.com/algorand/go-algorand-sdk/transaction"
 	"github.com/algorand/go-algorand-sdk/types"
 )
@@ -11,9 +14,12 @@ import (
 // MinTxnFee is v5 consensus params, in microAlgos
 const MinTxnFee = transaction.MinTxnFee
 
+// NumOfAdditionalBytesAfterSigning is the number of bytes added to a txn after signing it
+const NumOfAdditionalBytesAfterSigning = 75
+
 func setFee(tx types.Transaction, params types.SuggestedParams) (types.Transaction, error) {
 	if !params.FlatFee {
-		eSize, err := transaction.EstimateSize(tx)
+		eSize, err := EstimateSize(tx)
 		if err != nil {
 			return types.Transaction{}, err
 		}
@@ -1273,6 +1279,35 @@ func MakeApplicationCallTxWithBoxes(
 	return setFee(tx, sp)
 }
 
+// AssignGroupID computes and return list of transactions with Group field set.
+// - txns is a list of transactions to process
+// - account specifies a sender field of transaction to return. Set to empty string to return all of them
+func AssignGroupID(txns []types.Transaction, account string) (result []types.Transaction, err error) {
+	gid, err := crypto.ComputeGroupID(txns)
+	if err != nil {
+		return
+	}
+	var decoded types.Address
+	if account != "" {
+		decoded, err = types.DecodeAddress(account)
+		if err != nil {
+			return
+		}
+	}
+	for _, tx := range txns {
+		if account == "" || bytes.Compare(tx.Sender[:], decoded[:]) == 0 {
+			tx.Group = gid
+			result = append(result, tx)
+		}
+	}
+	return result, nil
+}
+
+// EstimateSize returns the estimated length of the encoded transaction
+func EstimateSize(txn types.Transaction) (uint64, error) {
+	return uint64(len(msgpack.Encode(txn))) + NumOfAdditionalBytesAfterSigning, nil
+}
+
 func parseTxnAccounts(accounts []string) (parsed []types.Address, err error) {
 	for _, acct := range accounts {
 		addr, err := types.DecodeAddress(acct)
diff --git a/future/transaction_test.go b/future/transaction_test.go
index 7f6da1eb..0bd207a7 100644
--- a/future/transaction_test.go
+++ b/future/transaction_test.go
@@ -7,7 +7,6 @@ import (
 	"github.com/algorand/go-algorand-sdk/crypto"
 	"github.com/algorand/go-algorand-sdk/encoding/msgpack"
 	"github.com/algorand/go-algorand-sdk/mnemonic"
-	"github.com/algorand/go-algorand-sdk/transaction"
 	"github.com/algorand/go-algorand-sdk/types"
 	"github.com/stretchr/testify/require"
 )
@@ -841,15 +840,15 @@ func TestComputeGroupID(t *testing.T) {
 	require.Equal(t, byteFromBase64(goldenTxg), txg)
 
 	// check transaction.AssignGroupID, do not validate correctness of Group field calculation
-	result, err := transaction.AssignGroupID([]types.Transaction{tx1, tx2}, "BH55E5RMBD4GYWXGX5W5PJ5JAHPGM5OXKDQH5DC4O2MGI7NW4H6VOE4CP4")
+	result, err := AssignGroupID([]types.Transaction{tx1, tx2}, "BH55E5RMBD4GYWXGX5W5PJ5JAHPGM5OXKDQH5DC4O2MGI7NW4H6VOE4CP4")
 	require.NoError(t, err)
 	require.Equal(t, 0, len(result))
 
-	result, err = transaction.AssignGroupID([]types.Transaction{tx1, tx2}, address)
+	result, err = AssignGroupID([]types.Transaction{tx1, tx2}, address)
 	require.NoError(t, err)
 	require.Equal(t, 2, len(result))
 
-	result, err = transaction.AssignGroupID([]types.Transaction{tx1, tx2}, "")
+	result, err = AssignGroupID([]types.Transaction{tx1, tx2}, "")
 	require.NoError(t, err)
 	require.Equal(t, 2, len(result))
 }
diff --git a/transaction/transaction.go b/transaction/transaction.go
index d112c60f..5c1ba7e8 100644
--- a/transaction/transaction.go
+++ b/transaction/transaction.go
@@ -4,6 +4,7 @@ import (
 	"bytes"
 	"encoding/base64"
 	"fmt"
+
 	"github.com/algorand/go-algorand-sdk/crypto"
 	"github.com/algorand/go-algorand-sdk/encoding/msgpack"
 	"github.com/algorand/go-algorand-sdk/types"