diff --git a/app/Support/Models/AccountBalanceCalculator.php b/app/Support/Models/AccountBalanceCalculator.php
index 8c27fbf0d4..56762b665c 100644
--- a/app/Support/Models/AccountBalanceCalculator.php
+++ b/app/Support/Models/AccountBalanceCalculator.php
@@ -60,9 +60,9 @@ class AccountBalanceCalculator
 
     private function getAccountBalanceByAccount(int $account, int $currency): AccountBalance
     {
-        $query                          = AccountBalance::where('title', 'balance')->where('account_id', $account)->where('transaction_currency_id', $currency);
+        $query = AccountBalance::where('title', 'balance')->where('account_id', $account)->where('transaction_currency_id', $currency);
 
-        $entry                          = $query->first();
+        $entry = $query->first();
         if (null !== $entry) {
             // Log::debug(sprintf('Found account balance "balance" for account #%d and currency #%d: %s', $account, $currency, $entry->balance));
 
@@ -81,9 +81,9 @@ class AccountBalanceCalculator
 
     private function getAccountBalanceByJournal(string $title, int $account, int $journal, int $currency): AccountBalance
     {
-        $query                          = AccountBalance::where('title', $title)->where('account_id', $account)->where('transaction_journal_id', $journal)->where('transaction_currency_id', $currency);
+        $query = AccountBalance::where('title', $title)->where('account_id', $account)->where('transaction_journal_id', $journal)->where('transaction_currency_id', $currency);
 
-        $entry                          = $query->first();
+        $entry = $query->first();
         if (null !== $entry) {
             return $entry;
         }
@@ -100,7 +100,7 @@ class AccountBalanceCalculator
 
     private function recalculateLatest(?Account $account): void
     {
-        $query  = Transaction::groupBy(['transactions.account_id', 'transactions.transaction_currency_id', 'transactions.foreign_currency_id']);
+        $query = Transaction::groupBy(['transactions.account_id', 'transactions.transaction_currency_id', 'transactions.foreign_currency_id']);
 
         if (null !== $account) {
             $query->where('transactions.account_id', $account->id);
@@ -115,12 +115,12 @@ class AccountBalanceCalculator
             $account             = (int) $row->account_id;
             $transactionCurrency = (int) $row->transaction_currency_id;
             $foreignCurrency     = (int) $row->foreign_currency_id;
-            $sumAmount           = $row->sum_amount;
-            $sumForeignAmount    = $row->sum_foreign_amount;
+            $sumAmount           = (string) $row->sum_amount;
+            $sumForeignAmount    = (string) $row->sum_foreign_amount;
 
             // first create for normal currency:
-            $entry               = $this->getAccountBalanceByAccount($account, $transactionCurrency);
-            $entry->balance      = bcadd($entry->balance, $sumAmount);
+            $entry          = $this->getAccountBalanceByAccount($account, $transactionCurrency);
+            $entry->balance = bcadd($entry->balance, $sumAmount);
             $entry->save();
 
             // then do foreign amount, if present:
@@ -146,8 +146,8 @@ class AccountBalanceCalculator
     }
 
     /**
-     * Als je alles opnieuw doet, verzamel je alle transactions en het bedrag en zet je dat neer als "balance after journal".
-     * Dat betekent, netjes op volgorde van datum en doorrekenen.
+     * Als je alles opnieuw doet, verzamel je alle transactions en het bedrag en zet je dat neer als "balance after
+     * journal". Dat betekent, netjes op volgorde van datum en doorrekenen.
      *
      * Zodra je een transaction journal verplaatst (datum) moet je dat journal en alle latere journals opnieuw doen.
      * Maar dan moet je van de account wel een beginnetje hebben, namelijk de balance tot en met dat moment.
@@ -158,7 +158,7 @@ class AccountBalanceCalculator
      */
     private function recalculateJournals(?Account $account, ?TransactionJournal $transactionJournal): void
     {
-        $query   = Transaction::groupBy(['transactions.account_id', 'transaction_journals.id', 'transactions.transaction_currency_id', 'transactions.foreign_currency_id']);
+        $query = Transaction::groupBy(['transactions.account_id', 'transaction_journals.id', 'transactions.transaction_currency_id', 'transactions.foreign_currency_id']);
         $query->leftJoin('transaction_journals', 'transaction_journals.id', '=', 'transactions.transaction_journal_id');
         $query->orderBy('transaction_journals.date', 'asc');
         $amounts = [];
@@ -169,24 +169,28 @@ class AccountBalanceCalculator
             $query->where('transaction_journals.date', '>=', $transactionJournal->date);
             $amounts = $this->getStartAmounts($account, $transactionJournal);
         }
-        $result  = $query->get(['transactions.account_id', 'transaction_journals.id', 'transactions.transaction_currency_id', 'transactions.foreign_currency_id', \DB::raw('SUM(transactions.amount) as sum_amount'), \DB::raw('SUM(transactions.foreign_amount) as sum_foreign_amount')]);
+        $result = $query->get(['transactions.account_id', 'transaction_journals.id', 'transactions.transaction_currency_id', 'transactions.foreign_currency_id', \DB::raw('SUM(transactions.amount) as sum_amount'), \DB::raw('SUM(transactions.foreign_amount) as sum_foreign_amount')]);
 
         /** @var \stdClass $row */
         foreach ($result as $row) {
-            $account                                 = (int) $row->account_id;
-            $transactionCurrency                     = (int) $row->transaction_currency_id;
-            $foreignCurrency                         = (int) $row->foreign_currency_id;
-            $sumAmount                               = $row->sum_amount;
-            $sumForeignAmount                        = $row->sum_foreign_amount;
-            $journalId                               = (int) $row->id;
+            $account             = (int) $row->account_id;
+            $transactionCurrency = (int) $row->transaction_currency_id;
+            $foreignCurrency     = (int) $row->foreign_currency_id;
+            $sumAmount           = (string) $row->sum_amount;
+            $sumForeignAmount    = (string) $row->sum_foreign_amount;
+            $journalId           = (int) $row->id;
+
+            // check for empty strings
+            $sumAmount        = $sumAmount === '' ? '0' : $sumAmount;
+            $sumForeignAmount = $sumForeignAmount === '' ? '0' : $sumForeignAmount;
 
             // new amounts:
-            $amounts[$account][$transactionCurrency] = bcadd($amounts[$account][$transactionCurrency] ?? '0', $sumAmount ?? '0');
-            $amounts[$account][$foreignCurrency]     = bcadd($amounts[$account][$foreignCurrency] ?? '0', $sumForeignAmount ?? '0');
+            $amounts[$account][$transactionCurrency] = bcadd($amounts[$account][$transactionCurrency] ?? '0', $sumAmount);
+            $amounts[$account][$foreignCurrency]     = bcadd($amounts[$account][$foreignCurrency] ?? '0', $sumForeignAmount);
 
             // first create for normal currency:
-            $entry                                   = self::getAccountBalanceByJournal('balance_after_journal', $account, $journalId, $transactionCurrency);
-            $entry->balance                          = $amounts[$account][$transactionCurrency];
+            $entry          = self::getAccountBalanceByJournal('balance_after_journal', $account, $journalId, $transactionCurrency);
+            $entry->balance = $amounts[$account][$transactionCurrency];
             $entry->save();
 
             // then do foreign amount, if present: