Free browser tool

Mortgage Extra Payment Planner

Compare the original amortization with monthly and one-time extra payments to estimate interest saved, payoff time and net savings after an entered fee.

Enter your values

Result

Enter the values and choose the main action.

Interest saved
Months saved
Net savings after fee
New payoff months

What this tool does

Compare the original amortization with monthly and one-time extra payments to estimate interest saved, payoff time and net savings after an entered fee.

How to use it

  1. Enter your values: Loan principal, Annual rate (%), Original term (years).
  2. Calculate
  3. Result: Interest saved, Months saved, Net savings after fee, New payoff months.

Formula and method

Each month calculates interest on the opening balance, then scheduled principal and optional extra principal. Net savings = base interest − accelerated interest − entered prepayment fee.

Worked example

For a 300,000 loan at 5% for 30 years, test 300 extra each month and a 10,000 payment in month 24.

Useful for

  • Testing recurring overpayments
  • Comparing a lump sum
  • Reviewing fees before paying

Limits and notes

Assumes a fixed rate and monthly payments. Contract restrictions, changing rates, taxes and opportunity cost of cash are not automatic.

Frequently asked questions

Is this an official decision or quote?

No. It is a planning result based only on your inputs. Confirm important decisions with the relevant provider or professional.

Are my entries stored?

No. This tool calculates in the current browser and does not send the values to Easynivo.

Content basis and verification

· Calculations run in your browser. Check the formula and assumptions on this page, and confirm important financial, tax, medical or legal decisions against current official guidance.
Maintained and reviewed by: Easynivo · Report a correction or source change