Affirm Installment Interest Calculator

Affirm is a loan. Pay in 4 often is not.

Affirm terms of 3 to 36 months usually carry an APR. Four-payment 0% products are closer to Afterpay or Klarna Pay in 4.

Use this page when checkout shows monthly payments and an APR, not when it shows four equal charges and 0% if paid on time.

Formula

r = APR / 12. If r = 0, payment = P / n. Else payment = P x r x (1+r)^n / ((1+r)^n - 1). Total = payment x n. Interest = total - P. Month-1 interest = P x r.

That is the same family of math as a simple loan EMI. The dedicated Simple Loan EMI calculator on this site is the general version; this page labels the Affirm checkout fields.

Pre-qualification is a later tool

The plan list includes a separate Affirm pre-qualification estimator. This installment page assumes you already know P, APR, and n.

Not tax, lending, or credit advice.

Frequently Asked Questions (FAQ)

What is the default $800 / 15% / 12 month result?

Monthly rate 1.25%. Payment is about $72.27, total paid about $867.24, interest about $67.24. Month-1 interest is $10.00 (800 x 0.0125).

What if my Affirm offer is 0% APR?

Set APR to 0. Payment = principal / months. $800 over 12 months is $66.67 per month and $0 interest. That promo still requires on-time payment.

Why might Affirm’s screen differ by a few cents?

Rounding, simple-interest vs amortization, and whether tax or shipping was financed. Trust the contract payment if it disagrees. This is a worksheet using the standard EMI formula.

Is this a pre-qualification estimator?

No. Affirm eligibility and the APR you are offered depend on underwriting. This page only prices a principal, APR, and term you already have (or are comparing).

Affirm Installment Interest Calculator

Calculator

Calculated Results

Affirm is a loan. Pay in 4 often is not.

Formula

Pre-qualification is a later tool

Frequently Asked Questions (FAQ)

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