Debt Payoff Extra
Compare paying off a loan with and without extra payments.
About Debt Payoff Extra
Adding extra to the standard payment pays down principal faster, reducing the months and interest. The comparison shows both how much sooner the debt ends and how much interest is saved. Even modest extra payments create outsized interest savings because they reduce the compounding base much earlier.
Formula
Debt Payoff Extra
Months = -ln(1 - r x B / P) / ln(1 + r); savings = interest without - interest with
- P
- monthly payment
- B
- balance
- r
- monthly rate
Worked example
With the default values below, Debt Payoff Extra returns Months with Extra of 38. Change any input above and every figure here is recalculated in your browser.
Inputs used
- Balance
- 10,000
- Annual rateaccepts 0–100 %
- 12 %
- Original term yearsminimum 1
- 5
- Extra payment
- 100
Results
- Standard Payment
- $222.44
- Months with Extra
- 38
- Interest Saved
- $1,093.78
Step by step
- 1Values used
- 2Debt Payoff Extra
- 3Months with Extra= 38
- 4Standard Payment= 222.44
- 5Interest Saved= 1,093.78
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 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.
- This is an estimate for general information and not professional financial, tax or legal advice. See the full disclaimer for the limits that apply to this kind of calculator.
How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.
Frequently Asked Questions
How is Debt Payoff Extra calculated?
Months = -ln(1 - r x B / P) / ln(1 + r); savings = interest without - interest with Adding extra to the standard payment pays down principal faster, reducing the months and interest. The comparison shows both how much sooner the debt ends and how much interest is saved.
Why does Debt Payoff Extra matter?
Even modest extra payments create outsized interest savings because they reduce the compounding base much earlier.
What values do I need to enter?
This calculator takes 4 inputs: Balance, Annual rate, Original term years, Extra payment. The pre-filled defaults are a realistic starting point — replace them with figures from your own environment for a result you can act on.