diff --git a/CRM/Grant/BAO/GrantBudget.php b/CRM/Grant/BAO/GrantBudget.php
index e2372bb..d4ba0a5 100644
--- a/CRM/Grant/BAO/GrantBudget.php
+++ b/CRM/Grant/BAO/GrantBudget.php
@@ -113,6 +113,20 @@ class CRM_Grant_BAO_GrantBudget extends CRM_Grant_DAO_GrantBudget {
       if ($grantBudget) {
         $balanceAmount = CRM_Utils_Rule::cleanMoney($grantBudget['balance_amount']);
         $amountGranted = CRM_Utils_Rule::cleanMoney($params['multifund_amount'][$k]);
+        // If there's a $grantId, we're updating an existing grant.  Make sure we don't
+        // double-count this money on validation.
+        if ($grantId) {
+          $oldGrantLineItem = civicrm_api3('EntityFinancialTrxn', 'get', [
+            'sequential' => 1,
+            'return' => ["financial_trxn_id.total_amount", "financial_trxn_id.trxn_date"],
+            'entity_table' => "civicrm_grant",
+            'entity_id' => $grantId,
+            'financial_trxn_id.from_financial_account_id' => $financialAccount,
+          ])['values'][0];
+          if ($oldGrantLineItem && $year == date('Y', strtotime($oldGrantLineItem['financial_trxn_id.trxn_date']))) {
+            $amountGranted -= $oldGrantLineItem['financial_trxn_id.total_amount'];
+          }
+        }
         if ($balanceAmount < $amountGranted) {
           $errors["multifund_amount[$k]"] = ts("The annual budget for this grant is {$grantBudget['budget']}. Grants totaling {$grantBudget['total_amount_granted']} have been made. {$grantBudget['balance_amount']} remains.");
         }