Installment Invoice Template
An installment invoice bills one scheduled part of a price the customer has agreed to pay over time, for example 'Installment 2 of 4, $1,250.00, due 1 December 2026, of a $5,000.00 project'. It differs from a deposit, milestone or progress invoice in what triggers it: a date on an agreed schedule, not a booking, a delivered stage or the amount of work done. There are two ways to run a plan. You can send one invoice for the full price and record each installment as a partial payment against it, or you can send a separate invoice for each installment as it falls due. Separate invoices give every installment its own number, due date and reminder, which is why this template is laid out for that method. Whichever you use, every invoice should repeat the plan: total price, installment number, the schedule of amounts and dates, what has been paid so far and what remains. The download is an editable HTML file with the usual invoice header, line table and totals, plus the installment fields below. Fill it in your browser, then print it or save it as PDF.
Preview this editable document
Download the HTML file to edit its fields, then print or save as PDF. Totals are entered manually.
What This Template Includes
- Payment plan or agreement reference and date agreed
- Total price of the plan, before and after tax
- Installment number (for example 2 of 4)
- Amount due for this installment (the invoice due date is its installment date)
- Full schedule: each installment's amount and due date
- Paid to date, with earlier invoice numbers
- Remaining balance after this installment is paid
- Interest, finance charges or fees, if any, shown separately
- What happens if an installment is missed
How to Create Your Installment Invoice
- 01
Describe your work
Type a plain English description of the services you provided, the client, and the amount.
- 02
AI generates your invoice
InvoiceQuickly's AI drafts the client, line items, dates, and totals for you to review before saving.
- 03
Review, download, and send
Check every detail, download the PDF, or use Pro to email the PDF directly to your client.
Recommended Payment Terms
The schedule is the payment terms, so write it into the agreement first and repeat it on every invoice: how many installments, the amount of each, the exact due dates and how they are paid. Use calendar dates ('due 1 December 2026'), not 'monthly' or 'at the halfway point'. Say what happens if one is missed: a grace period, a late fee if your agreement and local law allow it, or the right to make the whole remaining balance due. If you charge interest or a fee for paying over time, show it as its own line and state it in the agreement before the first invoice. In the US, a business that regularly lets consumers pay by written agreement in more than four installments (not counting a down payment), or charges them a finance charge, may be a creditor under the Truth in Lending Act's Regulation Z, which brings disclosure duties. Business-to-business plans are outside that rule. Check with an adviser before offering consumer payment plans at scale.
Need help writing payment terms? Read our guide to invoice payment terms for best practices and templates.
Tax Information
Splitting the price into installments does not usually split the tax point. If you issue one invoice for the full price, sales tax or VAT is normally charged on the full amount on that invoice, under the rules of the place where you are registered, even though the customer pays over several months. If you issue a separate invoice for each installment, each one carries the tax on its own amount, and the totals across the plan should add up to the tax on the full price. Some schemes let small businesses account for VAT when they are paid, but they often exclude long payment terms: the UK VAT Cash Accounting Scheme, for businesses with taxable turnover up to £1.35 million, cannot be used where a VAT invoice's payment terms are 6 months or more, or for goods sold on credit sale or hire purchase. InvoiceQuickly applies one tax percentage per invoice and copies saved tax IDs to new invoice PDFs. This is not tax advice; check with your tax authority or an adviser.
Industry context (2026)
Two official rules shape installment billing more than any industry convention. In the United States, Regulation Z, which implements the Truth in Lending Act, defines a creditor as a person who regularly extends consumer credit that is subject to a finance charge or is payable by written agreement in more than four installments (not including a down payment), and 'regularly' means more than 25 times in the preceding calendar year, or more than 5 times for transactions secured by a dwelling (12 CFR 1026.2(a)(17), published by the Consumer Financial Protection Bureau). That is why many consumer service businesses keep interest-free plans to four payments or fewer. In the United Kingdom, the VAT Cash Accounting Scheme lets businesses with estimated VAT taxable turnover of £1.35 million or less in the next 12 months pay VAT when customers pay, but HMRC excludes invoices with payment terms of 6 months or more, invoices raised in advance, and goods sold on lease purchase, hire purchase, conditional sale or credit sale; for those, VAT follows the normal invoice-based rules. Neither rule tells you how to lay out the invoice, but both decide whether a long plan creates disclosure duties or brings tax forward.
Worked example
Fernway Studio agrees a $5,000.00 website redesign with Calder Dental, a business client, payable in four equal installments of $1,250.00 on 1 November 2026, 1 December 2026, 1 January 2027 and 1 February 2027, with no interest and no tax charged in this example. Fernway sends one invoice per installment, a week before each date. INV-0031: 'Website redesign, installment 1 of 4', $1,250.00, due 1 November 2026. Notes: 'Plan total $5,000.00. Schedule: 1 Nov $1,250.00, 1 Dec $1,250.00, 1 Jan $1,250.00, 1 Feb $1,250.00. Paid to date $0.00. Remaining after this installment $3,750.00.' Calder pays in full. INV-0032, installment 2 of 4, due 1 December: notes show paid to date $1,250.00 (INV-0031) and remaining after this installment $2,500.00. On 1 December Calder pays only $800.00. Fernway records $800.00 as a partial payment on INV-0032, which leaves $450.00 open on that invoice and it stays unpaid. INV-0033, installment 3 of 4, still bills $1,250.00, and its notes show paid to date $2,050.00 ($1,250.00 + $800.00), INV-0032 balance of $450.00 overdue, and remaining after this installment $1,250.00 plus the $450.00 shortfall. Check: $1,250.00 + $800.00 + $450.00 open + $1,250.00 + $1,250.00 = $5,000.00. Keeping the shortfall on INV-0032 rather than adding it to INV-0033 means each invoice still matches one line of the agreed schedule.
Common mistakes to avoid
Billing installments with no schedule on the invoice
An invoice that says only 'Payment 2, $1,250' forces the client to dig out the agreement. Show the total, the installment number, every date and amount, and what is left.
Using one invoice when installments need chasing
One full-price invoice has one due date, so reminders and overdue status follow that date only. If installments fall due monthly and you need to chase each one, issue a separate invoice per installment.
Rolling a shortfall into the next installment
Adding a missed $450 to the next invoice breaks the link between invoices and the schedule and makes the debt look newer than it is. Leave the shortfall open on the invoice where it arose.
Hiding interest inside the installment
If you charge for paying over time, show it as a separate line agreed in advance. A plan quoted as interest-free that adds an unexplained amount to each installment invites disputes, and for consumer plans may need formal disclosure.
Charging tax per installment when it was due on the full invoice
If you issued a full-price invoice at the start, the tax on it is usually due under your normal accounting rules even though payment comes later. Do not add tax again on each installment invoice.
Invoicing Tips
- 1Number installments as 'n of N' in the first line description, so the client's accounts team can see where the plan stands without opening the agreement.
- 2Put the whole schedule in the notes of every invoice, with a paid or outstanding mark against each installment. One look shows both sides what is left.
- 3Match the invoice due date to the installment date exactly. A plan due on the 1st of each month needs invoices due on the 1st, not 30 days after you happen to send them.
- 4Ask the client to quote the invoice number on each payment, so a payment for installment 3 is not applied to installment 2.
- 5If an installment is paid short, record what arrived as a partial payment on that installment's invoice and leave the shortfall open there; do not quietly roll it into the next installment.
- 6Send each installment invoice a week or so before its due date. An invoice that arrives on the due date is late in the client's payment run.
Related Resources
- All invoice templates: industry, country and document-type layouts
- How to handle partial payments: recording and chasing short payments
- Milestone-based invoicing: when stages, not dates, should trigger payment
- Deposit invoicing guide
- Invoice payment terms guide
- Late fee calculator: simple interest on an overdue installment
Frequently Asked Questions
What is an installment invoice?
It is an invoice for one scheduled part of a larger price that the customer has agreed to pay over time. It shows the installment number, the amount and due date, the full payment schedule, what has been paid so far and the balance that remains.
Should I send one invoice or one per installment?
Both work. One full-price invoice with each installment recorded as a partial payment keeps everything on one document, but it has only one due date. A separate invoice per installment gives each payment its own due date, reminder and payment link, which is easier to chase. Agree the method with the client before the first payment.
How do I show the remaining balance on an installment invoice?
State three figures: the total price of the plan, the amount paid to date with the earlier invoice numbers, and the balance left after this installment. For example: plan total $5,000.00, paid to date $1,250.00 (INV-0031), this installment $1,250.00, remaining after this installment $2,500.00.
What is the difference between an installment invoice and a progress invoice?
An installment invoice is triggered by a date on an agreed schedule and usually bills an equal or fixed amount. A progress invoice bills the share of work completed during a period, so the amount changes each time. A milestone invoice is triggered by a delivered stage, and a deposit invoice secures a booking before work starts.
Can I charge interest on an installment plan?
Only if the customer agreed to it before the plan started and local law allows it. Show any interest or finance charge as its own line, never folded into the installment amount. For US consumer plans, charging a finance charge, or regularly allowing more than four installments, can bring Truth in Lending disclosure duties.
What happens if the client misses an installment?
Follow the agreement. Typical terms allow a short grace period, then a late fee where the law allows one, and finally let you demand the whole remaining balance. Send a reminder for the missed installment's own invoice, and do not issue the next installment invoice as if nothing happened.
Is an installment invoice the same as an IRS installment agreement?
No. An IRS installment agreement is a plan for paying a tax debt to the US government. An installment invoice is a business document a seller sends a customer for one payment under a commercial payment plan.
Can InvoiceQuickly handle installment payments?
There is no installment or payment-plan feature, but both methods work on every plan. Record each installment as a partial payment against one full-price invoice; the balance is tracked, the status stays unpaid until the last payment and the invoice PDF also shows recorded payments, applied credits and the remaining balance. Or create one invoice per installment with its own due date. On Pro, reminders and Stripe or PayPal links then apply to each installment, because a payment link charges the invoice's whole remaining balance.