Instalment Plan Cost Calculator

Work out instalment plan cost instantly with clear inputs, formula shown and shareable results.

About Instalment Plan Cost Calculator

Retail instalment plans quote a monthly figure rather than a rate. Solving for the rate that equates the financed amount with the instalment stream — an internal rate of return — reveals the credit cost hidden in the offer.

Formula

Implied rate

Financed = Σ instalment/(1+r)^t; APR = 12r

Worked example

With the default values below, Instalment Plan Cost Calculator returns Finance Charge of $8,000.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Cash Priceminimum 0: 80,000
Down Paymentminimum 0: 10,000
Monthly Instalmentminimum 0: 6,500
Number Of Monthsaccepts 2–60: 12

Results

Finance Charge: $8,000.00
Total Paid Including Down Payment: $88,000.00
Implied Annual Rate: 20.465%
Markup Over Cash Price: 10.00%

Step by step

1Values used
2Implied rate
3Finance Charge= 8,000.00
4Total Paid Including Down Payment= 88,000.00
5Implied Annual Rate= 20.465
6Markup Over Cash Price= 10.00

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 3 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
Figures are estimates. Lenders apply their own rounding, fees and eligibility rules, and rates change. This is not financial advice — confirm the numbers with your lender.
This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Figures are estimates. Lenders apply their own rounding, fees and eligibility rules, and rates change. This is not financial advice — confirm the numbers with your lender.

Frequently Asked Questions

Why compute an IRR?

Because the plan gives cash flows, not a rate. The IRR is the only rate consistent with those payments.

Are zero-cost plans really free?

Sometimes the interest is built into a higher sticker price, so compare against the best cash price you can negotiate.