diff --git a/backend/src/__tests__/gbt/gbt-tests.ts b/backend/src/__tests__/gbt/gbt-tests.ts
index 8619457ea..8927b4096 100644
--- a/backend/src/__tests__/gbt/gbt-tests.ts
+++ b/backend/src/__tests__/gbt/gbt-tests.ts
@@ -56,5 +56,11 @@ function mempoolFromArrayBuffer(buf: ArrayBuffer): ThreadTransaction[] {
 }
 
 function txidToOrdering(txid: string): number {
-  return parseInt(txid.slice(56).match(/../g)?.reverse().join('') as string, 16);
+  return (
+    ((parseInt(txid.substring(62, 64), 16) << 24) |
+      (parseInt(txid.substring(60, 62), 16) << 16) |
+      (parseInt(txid.substring(58, 60), 16) << 8) |
+      parseInt(txid.substring(56, 58), 16)) >>>
+    0
+  );
 }
diff --git a/backend/src/api/transaction-utils.ts b/backend/src/api/transaction-utils.ts
index 28861a997..92f5b71c5 100644
--- a/backend/src/api/transaction-utils.ts
+++ b/backend/src/api/transaction-utils.ts
@@ -158,7 +158,13 @@ class TransactionUtils {
 
   // returns the most significant 4 bytes of the txid as an integer
   public txidToOrdering(txid: string): number {
-    return parseInt(txid.slice(56).match(/../g)?.reverse().join('') as string, 16);
+    return (
+      ((parseInt(txid.substring(62, 64), 16) << 24) |
+        (parseInt(txid.substring(60, 62), 16) << 16) |
+        (parseInt(txid.substring(58, 60), 16) << 8) |
+        parseInt(txid.substring(56, 58), 16)) >>>
+      0
+    );
   }
 }