Spectra Calculator

← Borrowing smart

EIR (Effective Interest Rate)

The truer yearly cost to compare across loan offers.

EIR expresses the payment stream on a reducing-balance basis. A 3% flat car quote can be around 5% EIR; a 6% flat personal loan can be around 11% EIR.

Why it matters

Two providers can advertise similar flat rates but produce different true costs.

Quick tip

Choose the offer with the clearest EIR, fees and product disclosure sheet.

Work this out with your own numbers →