preclose the idea, explained

Prepayment · amortization · on your device

How Home Loan Prepayment Works — why one lump sum erases months, and when reduce‑tenure beats reduce‑EMI

You get a bonus. You could park it in the bank — or throw it at the loan. What actually happens to your loan if you do? Scroll, and watch it happen: the schedule rewritten, the interest that quietly evaporates, and the plain-English reason banks give you two choices when you prepay.

Scroll to watch ↓

The real problem

Your bank shows you an EMI. It never shows you the interest.

Every month your payment splits in two. Early in a loan, most of it is interest — rent on money you still owe. Only a sliver chips at the principal. That ratio is the whole game, and no bank statement draws it for you.

Illustrative split for a typical 20-year loan — your exact numbers come from the calculator.

How the prepayment works

One lump sum, and the whole curve dives.

A prepayment lands straight on the principal — the balance you owe. Interest is charged on that balance, so a smaller balance means less interest every remaining month. The saving compounds, and the loan reaches zero far sooner. That gap is months erased.

Outstanding-balance burn-down Two curves of the outstanding loan balance over time. The periwinkle baseline glides slowly to zero at the original end date. The amber with-prepayment curve drops sharply at a prepayment and reaches zero much earlier, leaving a hatched "months erased" span between the two closure points. start end ₹ months erased prepayment
Baseline — do nothing With one prepayment Months erased

Curves are illustrative of the shape, not your loan. The live calculator draws them to the paisa from your inputs.

The choice every bank offers

Reduce the tenure, or reduce the EMI?

When you prepay, the bank asks one question: keep your EMI the same and finish earlier, or keep the end date and pay less each month? Same lump sum, very different totals.

Reduce tenure

usually saves more

Your EMI stays the same. You keep paying the larger amount against a smaller balance, so the principal clears faster and the loan ends sooner.

Monthly payment
unchanged
Loan ends
much earlier
Total interest
lowest

Reduce EMI

easier on cash flow

Your end date stays the same. Each month costs less — useful if you need breathing room now — but you keep paying interest for the full original term.

Monthly payment
lower
Loan ends
same date
Total interest
saves less

◆ Same prepayment, reduce-tenure almost always wins on total interest — because you never lower the amount attacking the balance.

The guarantee

Your loan numbers never leave the device. The browser enforces it.

A prepayment calculator sees your salary, your loan, your bonus. The honest answer to “where does that go?” is: nowhere. The page ships a Content-Security-Policy that sets connect‑src 'none' — the browser itself refuses every network request the code could ever make.

No fetch, no analytics, no fonts, no CDN. Not a promise in a privacy policy — a rule the browser can't ignore.

What the tool actually does

Everything computed, nothing hidden.

  • Full amortization schedule

    Month-by-month opening balance, interest, principal, closing balance — grouped by year, reconciled to close at exactly ₹0.

  • One-time & recurring prepayments

    A single lump sum or an annual bonus every N months, each with an optional prepayment charge netted honestly out of the savings.

  • The side-by-side verdict

    Reduce-EMI vs reduce-tenure computed together: net interest saved, months erased, new EMI, new closure date, and a one-line call.

  • Twin burn-down chart

    The hero visual you just watched — drawn to the paisa from your loan, with the hatched months-erased span and closure tick.

  • CSV export & print

    The full rewritten schedule as RFC-4180 CSV, plus a clean print-to-PDF path for your records — no PDF library, no upload.

  • Honest-model note, on-screen

    Monthly-rest vs your bank's daily-reducing method is stated right beside the results — not buried in fine print.

Now run it on your own loan.

Type in your principal, rate and tenure, add the bonus you're thinking about, and see the exact interest saved, the months erased, and which strategy wins — all computed on your device, before you walk into the branch.

Open the preclose calculator →

Free · no account · works 100% offline · nothing leaves your device