Tools/Interest Rate Converter
Credit

Interest Rate Converter

Convert between flat (add-on) rates and effective interest rates (EIR). Understand the true cost of your loan beyond the advertised rate.

Interest Rate Converter

Convert flat monthly rates to effective interest rates (EIR) and factor rates.

The monthly add-on rate advertised by the bank (e.g. 0.99% or 1.5%).

Number of monthly installments for the loan.

How This Tool Works

How It Works

Philippine banks advertise add-on (flat) interest rates, but the true cost (Effective Interest Rate) is significantly higher. This tool converts between them.

Why EIR Matters

With add-on interest, you pay interest on the original principal every month, even though your balance decreases. The EIR accounts for this and shows the real annual cost.

Typical Conversion

  • 0.99% monthly flat rate ≈ 21-23% EIR per annum
  • 1.25% monthly flat rate ≈ 27-29% EIR per annum

Outputs

  • Flat Rate: Monthly and annual add-on rate
  • Total Interest %: Total interest as percentage of principal
  • EIR: Monthly and annual effective rate
  • Factor Rate: The multiplier per month (monthly payment / principal)

Related Tools