What an Extra $200 a Month Does to a 30-Year Mortgage

On an amortising loan, an extra payment does something structurally different from a normal one. Understanding why explains the size of the effect.

Where the money goes

A scheduled payment is split. Part covers the interest accrued since the last payment; the rest reduces principal. Early in the loan, most of it is interest, which is the mechanism covered in how loan amortisation works.

An extra payment is different. The interest for the period has already been covered by the scheduled payment, so an additional amount applied to principal reduces the balance directly. And because all future interest is calculated on the balance, that reduction eliminates every interest charge that principal would have generated for the remaining life of the loan.

That is the whole effect. You are not buying a discount; you are deleting future interest.

The numbers on a 30-year mortgage

Take $250,000 at 6.5% over 30 years. Principal and interest come to about $1,580 a month.

Paying as scheduled: 360 payments, and total interest of about $318,861. You pay more in interest than you borrowed.

Adding $200 a month: the loan clears in 265 months, a little over 22 years, with total interest of about $221,243.

The extra $200 a month:

• Saves roughly $97,600 in interest
• Ends the loan 95 months early, just under eight years

Total extra paid in is about $53,000. It removes $97,600 of interest. That ratio is the compounding effect running in your favour, and it is why extra payments early in a loan are so much more powerful than the same payments late.

Run your own balance and rate through our loan calculator and compare total interest across different terms to see the same effect on your numbers.

You have to tell the servicer where to put it

This is the practical trap. Send extra money without instruction and a servicer may:

• Hold it and apply it to next month's scheduled payment, which achieves almost nothing
• Park it in suspense until it adds up to a full payment
• Apply it to escrow rather than principal

Any of these can mean your extra payment does not reduce principal at all. You generally need to state explicitly that the additional amount is to be applied to principal, and then confirm on the next statement that the balance moved by the amount you expected. The CFPB advises checking that extra payments are credited as you intended rather than assuming.

Check for a prepayment penalty first

Some loans charge for paying ahead or paying off early. Prepayment penalties are restricted on many mortgages and are more common on other loan types. Read the note, or ask the servicer directly what happens if you overpay. A penalty does not always make prepaying wrong, but it changes the arithmetic.

When not to do this

Prepaying a loan is a guaranteed return equal to the loan's interest rate. That is genuinely good, and there are still several things that beat it:

• Higher-rate debt. Paying down a 24.99% card before a 6.5% mortgage is not close
• An unclaimed employer retirement match. An immediate 50% or 100% on the matched portion is a better return than any mortgage rate
• No emergency fund. Money paid into a mortgage is not accessible when the car fails. Home equity is not liquid, and needing to borrow it back later is expensive. See building an emergency fund
• A low fixed rate. If your rate is well below what a savings account pays, the arithmetic can favour saving instead

The ordering matters more than the enthusiasm. Prepaying a cheap mortgage while carrying an expensive card balance is a common and costly mistake.

Timing changes the value enormously

An extra payment removes all future interest on the principal it retires. The earlier it lands, the more future interest there is to remove. On a $250,000 loan at 6.5% over 30 years, a single extra $5,000 aimed at principal produces very different results depending on when it is made.

The same $5,000 is worth more than fifty times as much in year one as in year twenty-eight. This is not a quirk; it follows directly from the fact that principal retired early avoids interest for every remaining month.

The practical reading: if you are going to make extra payments at all, the beginning of a loan is when they matter. Late in a term, the money is usually better deployed elsewhere.

Small regular amounts versus occasional lump sums

Both work, and the mechanism is identical, but regular amounts are easier to sustain and land earlier on average.

On the same loan:

An extra $100 a month — around $3.30 a day — takes roughly five years off a 30-year mortgage. That is the whole case for the strategy, and it does not require a windfall.

The "one extra payment a year" approach produces a similar result and is often achieved by paying half the monthly amount every two weeks, which yields 26 half-payments, or 13 monthly equivalents, per year. Check that your servicer applies biweekly payments as they arrive rather than holding them and paying monthly, because some do the latter and the benefit disappears.

Telling the servicer where to put it

This is the step that most often goes wrong, and it can silently waste the entire effort.

Send extra money without instructions and a servicer may:

• Apply it to principal, which is what you want
• Hold it as a prepaid future payment, so next month's payment is covered and the balance is untouched
• Put it toward escrow, interest, or fees
• Return it

Only the first reduces your balance and saves interest. The others leave the amortisation schedule exactly where it was.

What to do:

1. Look for a "principal only" or "additional principal" field in the online payment form, and use it
2. If paying by cheque, write "apply to principal" on the memo line and include a note
3. Make the extra payment as a separate transaction from the regular one, which removes the ambiguity entirely
4. Check the next statement. The balance should have fallen by the full extra amount. If it has not, call
5. Confirm that extra payments do not cancel your next due date, since some servicers advance it and people then skip a month by accident

Step four is the important one. Verify once, and if the servicer handles it correctly you can rely on it afterwards.

Check for a prepayment penalty first

Some loans charge a fee for repaying early, or for repaying more than a set percentage of the balance in a year. These are restricted on many mortgages but are still found on some personal and auto loans.

Find the answer in your loan agreement before making a large payment. If a penalty exists, note whether it applies to full repayment only or to partial overpayments too, and whether it expires after a few years, which is common.

When not to do this

Extra principal payments are a guaranteed return equal to your loan's interest rate. That is genuinely good, but several things beat it:

• Higher-rate debt. Paying extra on a 6.5% mortgage while carrying a 22.99% card balance is a losing trade by a wide margin
• An employer retirement match, which is an immediate return no loan rate matches
• An emergency fund. Money paid into a mortgage is difficult to get back out; a job loss with a lower balance and no cash is worse than the reverse. See building an emergency fund
• A very low fixed rate, where the guaranteed return is small enough that other uses are plausibly better

There is also a liquidity point worth stating plainly. Overpaying does not reduce your required monthly payment; it shortens the term. You are converting accessible cash into a shorter loan, not into flexibility. Most lenders will not lower a required payment unless you formally recast the loan, which usually carries a fee.

Working out your own numbers

The variables are your balance, your rate, your remaining term, and the extra amount. Our loan calculator will show the baseline total interest, and how loan amortisation works explains why the early years are where the leverage is.

Sources

• CFPB: What is amortization?
• CFPB: Loan options
• CFPB: What is a personal loan?

Current as of August 2026. The loan amount and 6.5% rate are illustrative; figures cover principal and interest only, excluding taxes, insurance and escrow. Totals computed with monthly compounding.