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Installment calculator

What paying in installments really costs: the extra over the cash price, the yearly rate behind it, and when the last payment lands.

By Daniel Esteves

You pay $15.00 more than cash, a yearly rate of 89.1%. Done by week 6.
Left to pay

$315.00

Paid 1 of 4

  • Today$100.00
  • Week 2$105.00
  • Week 4$105.00
  • Week 6$105.00

How it is calculated

The calculator adds what you pay today to every installment and compares the total with the cash price: total = paid today + payments × each payment, and extra = total − cash price.

The yearly rate is the interest rate that makes those payments worth exactly what you financed, the cash price minus today's payment. It compounds over a year, like an effective annual rate, so a small fee on a short plan shows its real size.

As a formula: find the rate r per payment period where each payment × (1 − (1 + r)^−n) ÷ r = cash price − paid today, with n payments. The yearly rate is (1 + r)^k − 1, where k is 52 for weekly payments, 26 for every 2 weeks, and 12 for monthly. With the starting example, $300 financed in 3 payments of $105 every 2 weeks, r is about 2.48%, and (1.0248)^26 − 1 is about 89%.

Late fees are not included. Most plans charge one when a payment is late, which raises the real cost.

Questions

Is 0% interest really free?

If the payments add up to the cash price, yes, and the calculator says there is no extra cost. Check that the cash price is what you would pay without the plan.

Why is the yearly rate so high for a small fee?

Because the plan is short. With the starting example, $15 extra on a $400 order over six weeks works out to about 89% a year: the fee pays for six weeks of credit, not a year.

Can Outlayr track my installments?

Yes. Outlayr tracks purchases in installments from buy now, pay later apps such as Cashea, Klarna, and Afterpay, and from cards: the upfront payment, each installment, and any late fees, with a reminder the day before each one is due. For an order already in progress, take a screenshot of its payment plan and Outlayr fills in each payment and what is already paid. The free plan holds 2 installment apps, and each screenshot counts as one capture.

Is what I type saved?

No. The math runs in your browser, and nothing you type is stored or sent anywhere.

Track every expense in one sentence.

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