diff --git a/fuel-merkle/src/binary/merkle_tree.rs b/fuel-merkle/src/binary/merkle_tree.rs
index 276a36367d..fcfd39b455 100644
--- a/fuel-merkle/src/binary/merkle_tree.rs
+++ b/fuel-merkle/src/binary/merkle_tree.rs
@@ -221,8 +221,8 @@ where
         storage: StorageType,
         leaves_count: u64,
     ) -> Result<Self, MerkleTreeError<StorageError>> {
-        let mut nodes = Vec::new();
         let peaks = peak_positions(leaves_count).ok_or(MerkleTreeError::TooLarge)?;
+        let mut nodes = Vec::with_capacity(peaks.len());
         for peak in peaks.iter() {
             let key = peak.in_order_index();
             let node = storage
diff --git a/fuel-tx/src/transaction/metadata.rs b/fuel-tx/src/transaction/metadata.rs
index b66dde9b6b..5aada94850 100644
--- a/fuel-tx/src/transaction/metadata.rs
+++ b/fuel-tx/src/transaction/metadata.rs
@@ -81,7 +81,7 @@ impl CommonMetadata {
             .collect_vec();
 
         let mut offset = tx.inputs_offset();
-        let mut inputs_offset_at = Vec::new();
+        let mut inputs_offset_at = Vec::with_capacity(tx.inputs().len());
         for (index, input) in tx.inputs().iter().enumerate() {
             let i = offset;
             offset = offset
@@ -91,7 +91,7 @@ impl CommonMetadata {
         }
 
         let mut offset = tx.outputs_offset();
-        let mut outputs_offset_at = Vec::new();
+        let mut outputs_offset_at = Vec::with_capacity(tx.outputs().len());
         for (index, output) in tx.outputs().iter().enumerate() {
             let i = offset;
             offset = offset
@@ -101,7 +101,7 @@ impl CommonMetadata {
         }
 
         let mut offset = tx.witnesses_offset();
-        let mut witnesses_offset_at = Vec::new();
+        let mut witnesses_offset_at = Vec::with_capacity(tx.witnesses().len());
         for (index, witnesses) in tx.witnesses().iter().enumerate() {
             let i = offset;
             offset = offset