Mortgage Extra Payment Calculator (Interest Saved and Years Cut)
Early mortgage payments are almost entirely interest. On a 30-year loan at 6.2%, the first year's payments retire under 1.3% of the principal — which is exactly why an extra payment made in year two is worth several times the same payment made in year twenty. Overpayment reduces the balance that all future interest is calculated on.
Every extra $100 a month here removes roughly 3.4 years from the term.
| Extra per month | Payoff time | Total interest | Interest saved |
|---|---|---|---|
| $0 | 30.0 yrs | $421,711 | $0 |
| $100 | 26.6 yrs | $363,928 | $57,783 |
| $200 | 23.9 yrs | $321,536 | $100,174 |
| $300 | 21.8 yrs | $288,791 | $132,920 |
| $500 | 18.7 yrs | $241,027 | $180,684 |
| $1,000 | 13.9 yrs | $172,310 | $249,401 |
Where amortisation hides your money
The monthly payment is fixed, but its split shifts. At 6.2% on a 30-year term, the crossover where more of each payment goes to principal than interest arrives around year 18. Any extra payment jumps the queue by reducing principal directly, which compounds forward for the whole remaining term.
Bi-weekly payments versus one extra payment
Paying half the monthly amount every two weeks produces 26 half-payments — thirteen monthly payments a year instead of twelve. That is functionally an extra 8.3% payment, and it typically removes four to six years from a 30-year term. Making one deliberate extra payment a year achieves the same result with less admin.
Overpay or invest?
Overpaying earns a guaranteed, tax-free return equal to your mortgage rate. Above roughly 6% that is competitive with expected equity returns after tax, and it is risk-free. Below 4% the arithmetic usually favours investing — but check for early repayment charges and keep an emergency fund either way.
Interest saved on a $350,000 loan at 6.2% over 30 years
| Extra monthly | New term | Total interest | Interest saved |
|---|---|---|---|
| $0 | 30 yrs | $421,600 | — |
| $100 | 27.0 yrs | $369,300 | $52,300 |
| $250 | 23.3 yrs | $309,700 | $111,900 |
| $500 | 19.1 yrs | $245,100 | $176,500 |
| $1,000 | 14.2 yrs | $176,300 | $245,300 |
People also ask
How much does an extra $200 a month save on a mortgage?
On a $350,000 loan at 6.2%, roughly $95,000 of interest and about five years off the term — because the overpayment reduces the balance every future interest charge is based on.
Is it better to overpay the mortgage or invest?
Overpaying gives a guaranteed return equal to your interest rate. Above about 6% that generally beats risk-adjusted investing; below 4% investing usually wins over long horizons.
Do lenders charge for overpayments?
Many fixed-rate mortgages allow 10% of the balance to be overpaid each year penalty-free, with early repayment charges above that. Check your specific terms before committing.
Three worked examples
Same engine, three different starting points — useful if you want to see how sensitive the answer is before you type your own numbers in.
Example 1: loan amount 273000, currency "USD $"
On the lower / more conservative end. Every extra $100 a month here removes roughly 4.3 years from the term.
Example 2: loan amount 350000, currency "USD $"
A typical middle-of-the-road setup. Every extra $100 a month here removes roughly 3.4 years from the term.
Example 3: loan amount 455000, currency "GBP £"
On the higher / more demanding end. Every extra £100 a month here removes roughly 2.8 years from the term.
Quick answers about the Mortgage Extra Payment
What exactly does the Mortgage Extra Payment work out?
Early mortgage payments are almost entirely interest. You enter currency, loan amount, interest rate and loan term (plus 2 more optional details) and the result panel updates straight away, so you can compare two or three versions of the same question in a few seconds.
What do I need before I start?
Only 6 fields: currency, loan amount, interest rate, loan term, extra monthly payment and one-off lump sum today. Nothing else is needed and nothing is stored.
How is it calculated — where amortisation hides your money?
The monthly payment is fixed, but its split shifts. The same maths runs inside this page, so hand-checking the result on paper gives you the identical figure.
Why do two calculators give me different answers for mortgage Extra Payment?
Paying half the monthly amount every two weeks produces 26 half-payments — thirteen monthly payments a year instead of twelve. Different sites pick different assumptions, so always check which method a calculator states before you trust the gap between two numbers.
What does the "Interest saved on a $350,000 loan at 6.2% over 30 years" table on this page tell me?
It is the reference range this tool works against — 5 rows from "$0" (30 yrs) up to "$1,000" (14.2 yrs). Use it to sanity-check whether the number you just calculated sits where you expected it to.
Which currency should I pick?
The dropdown offers 5 choices — USD $, GBP £, EUR €, CAD C$ and AUD A$. Pick the one that matches your real situation rather than the one you would like to be true; currency usually moves the final figure more than any other single input, so it is worth running it twice with the option above and below your guess.
Does it work in both metric and imperial (or another currency)?
Yes. The "Currency" control converts every field and every result, so you never have to convert anything by hand before typing it in. Switch it after entering your numbers and the output re-renders instantly in the new system.
Do I have to press a button or reload the page to see the result?
No. Mortgage Extra Payment runs completely inside your browser, so the moment you change a value the cards recalculate — there is no submit step, no page reload and no waiting for a server round trip. That also means it keeps working on a weak or intermittent mobile connection.
Is it free, and do you keep what I type?
It is free with no sign-up, no app install and no usage limit. Nothing you enter into Mortgage Extra Payment leaves your device — the calculation is JavaScript running locally, so there is no upload of your figures to DrHint or anyone else.
Can I use it on a phone?
Yes — the layout stacks to a single column on small screens and the number fields open the numeric keypad on both Android and iOS. Many people bookmark this page or add it to their home screen and re-open it whenever the question comes up.
Anything to be careful about with the result?
On a $350,000 loan at 6. Treat the output as a well-grounded estimate for planning, not as a professional, legal or medical decision on its own.
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