Amortization Calculator — Your Full Payment Schedule

What an amortization schedule actually shows

An amortization schedule is just a table — every payment you'll make over the life of the loan, broken into how much goes to principal and how much goes to interest, plus your remaining balance after each one. This amortization calculator builds that full table for you instantly.

What most people notice first is how lopsided the early payments are. On a typical 30-year loan, well over half of your very first payment is interest, not principal. By the second-to-last payment near the end of the term, that ratio has almost completely flipped — nearly all of it goes to principal, with only a sliver left as interest.

Why interest is front-loaded

This isn't a trick or a lender's advantage baked in against you — it's just math. Interest is calculated on whatever balance you still owe, and that balance is at its highest the day you close. As you pay it down, the interest portion of each fixed payment naturally shrinks, and the principal portion grows to fill the gap.

It does mean, though, that paying off a mortgage early is most powerful in the early years. A dollar of extra principal paid in year 2 avoids decades of future interest on that dollar. The same extra dollar paid in year 28 barely moves the needle, since there's so little time left for interest to accrue on it anyway.

The real power of extra payments

Because interest is front-loaded, extra payments are disproportionately powerful early on. Every extra dollar you send goes straight to principal, skipping the interest split entirely — which means it also skips every future month of interest that dollar would otherwise have accrued.

On a roughly $400,000 loan, an extra $200 a month can save well over $100,000 in interest over the life of the loan and cut years off the payoff date, according to typical lender payment calculators. The exact numbers depend on your rate and balance, but the pattern holds everywhere: extra payments made earlier do more work than the same dollars paid later.

Try it yourself — set the extra monthly payment field above to any amount and watch the "interest saved" and "time saved" figures update. Even a modest, sustainable extra payment tends to outperform people's expectations.

Three factors that shape your schedule

Loan term is the biggest lever. A 30-year loan amortizes slowly and keeps monthly payments lower; a 15-year loan amortizes fast, builds equity quickly, and costs far less in total interest — at the cost of a noticeably higher payment.

Interest rate directly controls how much of every early payment goes to interest instead of principal. A higher rate means a slower start to building equity, even with an identical loan amount and term. It's worth noting this is different from your APR, which folds in points and fees — the amortization schedule itself runs on the interest rate alone.

Extra payments are the one factor you control after closing. Whether it's a consistent extra amount every month or an occasional lump sum — a bonus, a tax refund, an inheritance — both accelerate the schedule in exactly the way this calculator lets you model.

How to use this calculator

Enter your loan amount, rate and term the same way you would for our standard mortgage calculator. If you want to see the effect of paying extra, add an amount to the "extra monthly payment" field, or use the one-time lump payment field for something like a bonus applied in a specific month.

The year-by-year table above updates instantly, and the headline numbers show your total interest with and without the extra payments side by side, so the savings are immediately obvious rather than buried in a table you have to interpret yourself.

Why this doesn't work for adjustable-rate mortgages

This calculator, like every standard amortization tool, assumes one fixed rate for the entire term. That works perfectly for a fixed-rate mortgage, and it even works for the introductory fixed period of an ARM.

Once an ARM's rate starts adjusting, though, nobody — not this calculator, not your lender — can predict future payments with certainty, since future rates are unknown. If you have an ARM, treat any amortization schedule as accurate only through the end of your fixed-rate period.

Extra payments versus a loan recast

Making steady extra payments, as modeled here, doesn't change your required monthly payment — it just shortens the loan and cuts total interest, while you keep paying the same amount each month until it's paid off early.

A loan recast is a different move: you make one large lump-sum payment, then ask your lender to recalculate a lower required monthly payment on the same rate and remaining term. It's worth understanding the distinction, since they solve different problems — recasting lowers your monthly obligation, while extra payments shorten your timeline.

The biweekly payment strategy

One popular way people build extra payments into their routine without really noticing is switching to biweekly payments instead of monthly ones. Instead of one monthly payment, you pay half that amount every two weeks.

Because there are 52 weeks in a year, this quietly adds up to 26 half-payments — the equivalent of 13 full monthly payments instead of 12.

That extra payment every year functions exactly like the "extra monthly payment" field in the calculator above, just delivered as one annual lump sum instead of spread out. Not every lender supports true biweekly billing, so it's worth asking, but you can replicate the same effect yourself by simply adding one-twelfth of your payment to what you send each month.

15-year versus 30-year amortization, side by side

It's worth seeing the full trade-off in one place rather than just conceptually. Toggle the loan term in the calculator above between 15 and 30 years on the same loan amount and rate — or run both through our loan comparison calculator side by side, and two things happen at once: the monthly payment rises noticeably, and the total interest paid over the life of the loan drops dramatically.

Neither term is objectively correct — it depends on whether your budget can comfortably absorb the higher 15-year payment, and what else you'd do with the monthly difference if you chose the 30-year term instead, whether that's investing it, building an emergency fund, or simply having more breathing room.

How amortization connects to your home equity

Your equity — the portion of the home you actually own outright — grows exactly in step with the principal column of this amortization schedule, combined with any appreciation in the home's value. In the early years of a mortgage, equity from paydown alone builds frustratingly slowly, since so little of each payment reduces the balance.

This is part of why extra payments matter so much to people planning to sell or refinance in the medium term. Building equity faster through extra principal payments gives you more flexibility later — a bigger down payment on a move-up home, more room to refinance without PMI, or simply a smaller balance if you decide to sell.

A common misconception worth clearing up

Some borrowers assume that because their statement shows a fixed monthly payment, their loan balance drops at a steady, even pace every month. This calculator makes it obvious that's not how it works — the amount going to principal grows every single month, even though the total payment stays flat.

That's also why paying extra earlier is more powerful than paying the same extra amount later, and why two people with identical loans who take different approaches to extra payments can end up years apart in their actual payoff date, even paying the exact same total amount over time depending on when they paid it.

Why refinancing resets your amortization curve

Every time you refinance, your amortization schedule starts over at month one, regardless of how far along you were on the original loan. This means a fresh round of mostly-interest payments in the early months of the new loan, even if you were well past that phase on the loan you refinanced away from.

This isn't automatically a bad thing if the new rate is meaningfully lower, but it's worth understanding clearly — a lower monthly payment after refinancing doesn't necessarily mean you're building equity faster, since more of each new payment is going to interest again, at least initially. Running the numbers through our refinance calculator alongside this one gives the fuller picture.

What happens with interest-only or negative-amortization loans

This calculator assumes a standard, fully-amortizing loan, where every payment includes at least some principal from day one. Two less common loan structures work differently and deserve a brief mention. An interest-only loan lets you pay just the interest for a set period, meaning your balance doesn't shrink at all during that phase — the amortization only begins once the interest-only period ends.

A negative-amortization loan, rarer still and generally best avoided, allows a minimum payment so low it doesn't even cover the interest due, meaning your balance actually grows over time instead of shrinking. Neither structure is modeled by this calculator, since both represent a meaningfully different — and generally riskier — repayment pattern than the standard amortizing loans most borrowers have.

Amortization and mortgage interest deductions

Because interest is front-loaded, the early years of a mortgage generate the most mortgage interest available to potentially deduct if you itemize on your tax return. This deduction shrinks year by year as your amortization schedule shifts more of each payment toward principal, which is worth knowing if you're weighing the tax angle of extra payments or a shorter loan term.

Since the standard deduction nearly doubled in 2018, a majority of homeowners no longer itemize, meaning this effect doesn't apply to most borrowers in practice — but it's worth checking your own situation with a tax professional rather than assuming either way, especially in the higher-interest early years this calculator's table highlights clearly.

Amortization on a second mortgage or HELOC

If you have a second mortgage or a HELOC that's entered its repayment period, it amortizes using the exact same math this calculator models — its own separate schedule, running independently of your first mortgage's amortization. Two loans on the same property means two separate front-loaded interest curves, which is worth keeping in mind when estimating your total household debt paydown over time.

Running each loan through this calculator separately, using its own balance, rate and term, gives an accurate combined picture rather than trying to estimate blended payments by hand.

A simple habit: checking your amortization once a year

Most mortgage statements show your current balance but not necessarily how much of your last payment went to principal versus interest, or how that split compares to a year ago.

Running your loan through this calculator once a year, updating the remaining balance and years left, gives a quick, concrete sense of how much progress you've actually made — often more encouraging than it feels from the monthly statement alone, especially once you're several years into a long-term loan.

This is also a useful moment to reconsider whether an extra payment strategy still makes sense given your current financial situation, since priorities and available cash flow naturally shift over the years a mortgage is open.

Why small rounding differences are normal

If you compare this calculator's numbers against your lender's official amortization schedule, you may notice tiny differences of a few cents or a few dollars here and there. This is completely normal and comes down to how each system handles rounding at each payment and how leap years or exact day counts get treated in slightly different ways between calculators.

These differences are cosmetic, not meaningful — the overall shape of your amortization curve, your approximate payoff date, and your total interest estimate will all match closely enough for planning purposes, even if the exact penny-level figures don't align perfectly with your servicer's official numbers.

Using amortization to compare loan offers

Beyond planning around a single loan, this calculator is a useful side-by-side tool when comparing two or three offers from different lenders. Running each offer's rate and term through separately reveals not just the monthly payment difference but how the total interest and payoff timeline compare, which a headline rate alone doesn't show.

Pairing this with our loan comparison calculator for the fee side of each offer gives a genuinely complete picture before committing to any specific lender.

Why your payoff date can shift even without extra payments

If you've made all your regular payments on schedule with no extra amounts, your original payoff date shouldn't move at all — the schedule is fixed at closing for a standard fixed-rate loan.

If your projected payoff date seems to have shifted when you re-run this calculator, the most common cause is simply a change in one of your inputs, like an updated remaining balance that doesn't perfectly match the original schedule due to a skipped or late payment somewhere along the way.

Checking your latest official mortgage statement for your exact current balance before re-running this calculator avoids this kind of small discrepancy and keeps your projection aligned with your loan's actual, current status. When in doubt, your servicer's own online portal typically shows the exact current balance and next payment breakdown, which is the most reliable source to plug into this or any other amortization tool.