Invoice Balance Calculator
Check the money still due on one invoice, or identify an overpayment. Keep credits, cash received and refunds separate so the same adjustment is not counted twice.
Check one invoice balance
Use one currency with two decimal places throughout. Enter 0 for none. Amounts stay in this calculator's memory and are not saved or sent by this tool. A page refresh resets them.
Adjusted invoice: 900.00
Net payments retained: 400.00
Amount still due: 500.00
1,000.00 − 100.00 − 400.00 + 0.00 = 500.00
Arithmetic only. This does not issue a credit note, validate tax treatment, update an invoice, or determine whether money is legally owed. Do not treat processor fees as customer underpayment.
The balance formula
Original invoice − valid credits − payments received + cash refunded = balance. A positive result is an amount still due. Zero means the entered records settle. A negative result is a customer credit or overpayment to resolve, not another invoice to send.
Use amounts for one invoice and one currency only. Enter the original total including tax and tax-inclusive credits where applicable. This tool supports two-decimal amounts; it does not convert currencies or calculate tax, interest, fees, exchange gains or withholding.
Worked example: a partial payment and a scope reduction
A fictional invoice totals 1,000.00. An agreed reduction is documented as a valid 100.00 credit. The client has paid 400.00 and received no refund. The adjusted charge is 900.00, the net payment is 400.00, and the remaining balance is 500.00. The tool starts with those amounts.
If the client had already paid 1,000.00, the same credit would leave a 100.00 customer credit. Recording a completed 100.00 refund would then settle the account. Enter a refund only after the cash is actually returned; a proposed refund is not a completed payment event.
Common reconciliation traps
- Deposit counted twice: only include payments allocated to this invoice. A separately invoiced deposit may require a different accounting allocation.
- Processor fees: a client who pays 400.00 has not necessarily underpaid because your provider deposits 388.00. Reconcile the gross payment and the fee separately.
- Refund without an adjustment: returning cash increases the calculated balance unless a valid reduction also changes the charge. Confirm the reason and documentation.
- Unallocated cash: a bank transfer may cover several invoices. Get remittance details before allocating the whole amount here.
Keep the evidence behind the total
The calculator is a check, not a ledger. Keep invoice numbers, payment dates, transaction references, credit-note references and refund evidence in your records. The IRS recordkeeping guidance explains the role of supporting documents for US business records; requirements and retention periods depend on your jurisdiction.
Use the partial-payment workflow, correction guide and downloadable reconciliation worksheet to document the result. Create the underlying document with the invoice generator; this calculator does not change saved drafts.