Installment Plan Calculator

About this calculator

An installment plan splits the cost of a purchase into a series of equal payments over time, either interest-free — common in retail "buy now, pay later" offers — or with interest added, in which case the payment is calculated with the standard amortizing loan formula so that principal and interest are spread evenly across the term.

The key difference between an installment plan and a general-purpose loan is that it is typically tied to a specific purchase and offered at the point of sale, often by the retailer or a third-party financing partner rather than a bank, and it may carry promotional 0% interest for a limited window before a standard rate applies. This calculator works out the monthly payment for an installment purchase, with or without interest, from the price, term, and rate you specify.