Loan Amortisation Factor Calculator

Work out loan amortisation factor instantly with clear inputs, formula shown and shareable results.

About Loan Amortisation Factor Calculator

The amortisation factor, also written (A/P, r, n), is the payment per unit of loan that exactly clears principal and interest over the term. Multiply it by any loan size to get the level instalment.

Formula

Amortisation factor

A/P = r(1+r)^n / ((1+r)^n - 1)

r: Rate per period
n: Number of payments

Worked example

With the default values below, Loan Amortisation Factor Calculator returns Amortisation Factor (A/P) of 0.00805593. Change any input above and every figure here is recalculated in your browser.

Inputs used

Loan Amountminimum 0: 250,000
Annual Interest Rateaccepts 0–100 %: 7.5 %
Term In Yearsaccepts 1–50: 20
Payments Per Yearaccepts 1–52: 12

Results

Amortisation Factor (A/P): 0.00805593
Payment Per Period: $2,013.98
Total Repaid: $483,355.92
Total Interest: $233,355.92

Step by step

1Values used
2Amortisation factor
3Amortisation Factor (A/P)= 0.00805593
4Payment Per Period= 2,013.98
5Total Repaid= 483,355.92
6Total Interest= 233,355.92

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 or fees or charges into account.
Figures are rounded for display to 8 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

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

Frequently Asked Questions

Why use a factor instead of the payment directly?

Because the factor is independent of loan size, so one number prices every loan at that rate and term.

What if the rate is zero?

The factor becomes 1/n, meaning the loan is simply repaid in equal slices of principal.