How it works
Enter the balance you owe today and the monthly payment your lender requires. The calculator then builds two schedules side by side: one where you pay only the required amount, and one where you add extra principal every month. A one-time lump sum goes into the faster schedule only, and it's counted in your total cash paid so it never looks like free savings.
Each month's interest and payment is rounded to cents, and the last payment clears whatever is left. The required payment has to be large enough to cut into principal, and the tool stops with an error if repayment would run past 600 months. Your bank may charge interest daily or apply extra money differently, so treat this as a plan and ask the lender for a written payoff quote when you're ready to close the loan.
The formula behind the estimate
Every result starts with a defined model and visible assumptions.
Monthly interest = opening balance × annual contract rate ÷ 1,200 Payment applied = min(required payment + extra, balance + monthly interest) Closing balance = opening balance + interest − payment applied Interest saved = scheduled interest − accelerated interest An immediate lump sum reduces principal before month one.
A worked example
Say you owe 12,000 at 0% and your required payment is 1,000 a month. That takes 12 months. Add 200 a month and it's gone in 10, so you finish two months sooner and save no interest, because none was being charged. At a positive rate, the same extra payments would also cut interest. Any currency works as long as every amount uses the same one. These numbers are illustrative.
Should I use this or the car loan calculator?
Use this page when you already have a loan and want to know what extra payments would do. The car loan calculator is for a purchase you haven't made yet: it starts from the vehicle price, down payment, taxes, fees and trade-in. A lender's payoff quote can also include accrued interest and fees that aren't part of the principal balance, so the quote may be a little higher than the balance on your statement.
Does the currency choice change the result?
No. USD, PKR, INR, GBP, CAD, AUD, AED and EUR only change labels and formatting. Nothing is converted, and no local rates, bank policies or legal rules are loaded. The model assumes a fixed monthly payment with interest charged on the declining balance, so it doesn't fit flat-rate, balloon, PCP, Ijarah or Musharakah contracts. The linked sources describe general concepts in the United States.
Questions worth asking
Is the result my lender's settlement amount?
No. This is a planning estimate, and your lender's dated settlement quote is the number that counts. Daily interest, unpaid charges and prepayment terms can all change the amount due on the day you pay it off.
What happens if my payment doesn't cover the interest?
The calculator stops and asks you to check or raise the required payment. When a payment is smaller than the monthly interest, the balance grows, and the tool won't invent a balloon payment to hide that.
How does a lump sum work in this calculator?
A lump sum reduces your principal right before the first modeled month. It can't be larger than the balance you entered, and it's included in total cash paid so the comparison stays honest.
Do extra payments help on a 0% loan?
They shorten the loan but save no interest, since a 0% loan doesn't charge any. The benefit is finishing sooner, which only matters if you'd rather have the debt gone than have the cash available.
Does choosing PKR or EUR convert my loan?
No. The currency setting only changes how amounts are labeled. Enter your balance and payment in the currency you're using; no exchange rate or local loan eligibility is applied.
This is general information, not personalized financial advice. Read the limitations.
