Installment Plan

An installment plan (British spelling: instalment plan) is an arrangement to pay for a purchase, or repay a debt, through a fixed number of scheduled payments instead of a single lump sum. Each payment is usually the same size and falls on a set date, and the plan ends when the last one is made. Installment plans finance cars, furniture, phones, appliances and education, and they are the basic structure of most personal loans and mortgages.

In credit law an installment plan is closed-end credit: the amount, the number of payments and the end date are fixed at the start. That sets it apart from revolving credit such as a credit card, where the borrower can borrow again as the balance is repaid. Modern variants include card-linked installment features and buy now, pay later plans offered at the checkout.

An installment plan is like slicing a big bill into equal pieces and paying one slice a month. You take the sofa home today, and instead of paying the full price now you agree to pay, say, twelve equal slices over a year.

Someone has to wait for the money, so there is often a charge for the wait, built into the slices. Sometimes the shop or the lender absorbs that charge to win the sale, and the plan is advertised as interest-free. Either way, the deal is fixed from the start: you know how many slices, how big, and when the last one is due.

• Installment loans. A bank or finance company lends a fixed sum, such as a car or personal loan, repaid in equal monthly payments of interest and principal.
• Retail installment contracts and hire purchase. The seller, or a finance company working with it, finances the goods; under UK hire purchase the buyer does not own the goods until the final payment.
• Card installment plans. Some card issuers let a cardholder convert a purchase on their card into fixed monthly payments for a set fee or rate, and some card networks offer installment services that merchants and issuers can switch on. In Brazil, paying for goods in monthly installments on a credit card ("parcelado") is a long-standing everyday practice.
• Buy now, pay later. Short-term plans, often four payments over six weeks, offered at the point of sale or online, usually with no interest if paid on time and with late fees if not.
• Equated monthly installments (EMI). The common term in India and South Asia for the fixed monthly payment on loans and consumer-durable finance.
• Islamic installment sales. Under murabaha, a bank buys an asset and sells it to the customer at a disclosed mark-up payable in installments, so the bank earns a trading profit rather than interest.

For a plan that charges interest on the declining balance, each equal payment covers that month's interest and repays some principal; this is amortization. The standard calculation is:

• $A$ is the regular payment.
• $P$ is the amount financed (the principal).
• $r$ is the interest rate per period, written as a decimal (an annual rate divided by 12 for monthly payments).
• $n$ is the number of payments.

Worked example: $1,200 financed over 12 months at an annual rate of 12% gives $r = 0.01$ and $n = 12$. The payment is $1{,}200 \times 0.01 \div (1 - 1.01^{-12}) \approx 106.62$, so the buyer pays about $106.62 a month and $1,279.42 in total. The difference, $79.42, is the finance charge. In early months most of each payment is interest; by the last months, almost all of it is principal.

When a plan is advertised as 0%, $r = 0$ and the payment is simply $P \div n$, or $100 a month in the example. The cost of the credit is then usually paid by the merchant, through a discount to the lender, or recovered from late fees, and the buyer should check for set-up fees that make the true annual percentage rate above zero.

In the US, closed-end consumer credit is covered by the Truth in Lending Act and Regulation Z, which require a disclosure of the amount financed, the finance charge, the APR, the total of payments and the payment schedule before the contract is signed. Pay-in-four BNPL plans with no finance charge sit largely outside those disclosures: a 2024 Consumer Financial Protection Bureau interpretive rule that would have treated some BNPL products like credit cards was withdrawn in May 2025, and some states, such as New York, have moved to license BNPL lenders.

In the UK, regulated installment credit falls under the Consumer Credit Act and the Financial Conduct Authority. Interest-free BNPL, called deferred payment credit, came under FCA regulation on 15 July 2026, bringing affordability checks and access to the Financial Ombudsman Service for agreements made from that date. In the EU, the revised Consumer Credit Directive (EU) 2023/2225 applies from 20 November 2026 and brings most interest-free and short-term BNPL into scope.

Installment plans make large purchases affordable, give a predictable budget and, when reported to credit bureaus, can help build a credit history. For merchants they raise conversion and basket size, which is why retailers often subsidise them.

The risks are mainly behavioural and contractual. Several plans running at once can strain a household budget; missed payments bring fees and may lead to default, repossession under hire purchase, or damage to a credit score. Deferred-interest offers can charge back-dated interest on the whole purchase if the balance is not cleared in time. Where lenders do not check affordability, installment credit shades into predatory lending. Digital lending platforms have made plans faster to take out.

• Consumer Financial Protection Bureau — Regulation Z (Truth in Lending)
• Financial Conduct Authority — Buy now pay later