Convert effective and addon rates

Generate bidirectional conversions between effective annual rate and addon rate by payment count.

If calculation UI does not appear, reload with JavaScript enabled. Related context links below remain available.

Calculation specification

Reviewed on:

Formula basis

From annual rate R, total-term addon rate A=n×(R/m)/{1−(1+R/m)^−n}−1. In the reverse direction, the periodic annuity rate is solved by bisection and annualized as m times that rate.

Calculation method

Converts an entered annual effective-style rate or total-term addon rate in both directions for each payment count in a table.

Exclusions and checks required

  • The displayed addon rate is interest divided by principal over the row's entire term, not an annual addon rate.
  • The annual side is a nominal periodic-rate multiple, not an APR including fees or actual days.

Example input:：Converting a 10% entered annual rate across monthly payment counts

rate
10
rateType
effective
periodsPerYear
12
maxPeriods
60
step
6
digits
3

Check the selected rate type and do not compare the total-term addon percentage directly with a differently defined annual rate.

FAQ

Who is this calculator for? Convert effective and addon rates

Generate bidirectional conversions between effective annual rate and addon rate by payment count.

What values should I enter?

Applies to: Addon loans / A = n × (R/m) ÷ {1 − (1+R/m)^−n} − 1

How should I interpret this estimate?

Converts an entered annual effective-style rate or total-term addon rate in both directions for each payment count in a table.

How to use

  1. Enter your input values and press Calculate.
  2. Review the result and compare it with expected context.
  3. From annual rate R, total-term addon rate A=n×(R/m)/{1−(1+R/m)^−n}−1. In the reverse direction, the periodic annuity rate is solved by bisection and annualized as m times that rate.