How do you track partial payments against an invoice?

Question

Sheet Reserve · Accepted Answer

Keep one invoice record with its original amount and cumulative payments, then calculate outstanding balance as invoice amount less payments. A $1,250 invoice with $500 paid has $750 outstanding. A further $300 payment reduces the balance to $450. If payments are kept in a separate ledger, sum them by the stable invoice ID before calculating the remaining amount.

Do not repeat the full invoice amount on a new row for each payment. That duplicates the receivable in an invoice total.
Should an invoice tracker hide overpayments?
No. Invoice amount less payments can be negative when a customer overpays. Keep that balance visible for review rather than flooring it at zero and losing the credit information.