Why is my lender's payment a few dollars different from mine?

Rounding. Lenders round the payment and true up the final one against the residual balance, which is why the last month of a schedule looks lopsided. A difference of a dollar or two is normal; a difference of hundreds means a different rate, term or fee assumption.

Why is my payment almost all interest in the early years?

Interest in any month is the rate times the previous balance, and the balance starts at its maximum. On a 30-year loan at 6.9% the first year is about 86% interest. The only way to change the shape of that is to attack the balance early, which is what paying extra does.

Finance & LoansmortgageUnited States only

HELOC Payment Calculator

Payment on a home equity line once it enters the repayment phase, amortising the drawn balance over the remaining term.

Also called: home equity line of credit payment.

HELOC draw amount

Type "250k", "1.2m" or the plain number, all of them parse.

Interest rate (per year)

Tenure

years

Payment frequency

Paying quarterly or yearly instead of monthly changes the interest, not just the instalment.

Instalment frequency

Fewer, larger instalments means the balance sits higher for longer, so total interest rises even though each payment covers more principal.

Prepayments and extra payments

A lump sum, a standing extra amount, or both. The schedule and the saving are recomputed against them.

Extra paid with every instalment

A standing amount on top of the payment. This is what a round-up-your-mortgage plan does.

One-off prepayment

Paid after this many instalments

Leave at 0 if you are not making a lump-sum prepayment.

Fees and ongoing charges

Processing fees raise your effective rate; insurance and maintenance raise your real monthly outgo.

Processing and other up-front fees

Deducted from what you receive but charged on the full loan, so they raise your APR without changing the instalment.

Insurance, maintenance or other monthly charges

Not part of the loan, but part of what leaves your account each month.

Interest-only period before repayment

Months before repayment starts, and whether the interest accruing in them is capitalised. The same arithmetic covers a study-period holiday, a deferment and a payment pause.

Interest-only months before repayment starts

I will pay the interest during that period

If you do not, it is added to the loan, which is why an education loan is often larger when repayment begins than the amount that was disbursed.

Monthly instalment

$492.37

$492.37 a month for 15 years. Over the full term you repay $88,626.56, of which $38,626.56 is interest. 77.25% of what you borrowed.

Total interest

$38,626.56

Total repayment

$88,626.56

Interest as % of principal

77.25%

Interest in period 1

$354.17

Principal in period 1

$138.20

How this is calculated

An estimate, not an offer or a guarantee. Projected returns assume the rate you entered holds for the whole term, which no market does.

Where your money goes

Principal $50,000 (56%)Interest $38,627 (44%)

Outstanding balance

Hover or drag for values

Outstanding balance

180 rows

Month	Payment	Interest	Principal	Balance
1	$492	$354	$138	$49,862
2	$492	$353	$139	$49,723
3	$492	$352	$140	$49,582
4	$492	$351	$141	$49,441
5	$492	$350	$142	$49,299
6	$492	$349	$143	$49,156
7	$492	$348	$144	$49,012
8	$492	$347	$145	$48,867
9	$492	$346	$146	$48,720
10	$492	$345	$147	$48,573
11	$492	$344	$148	$48,425
12	$492	$343	$149	$48,275

Method and background

This is what the calculation gives for the numbers you entered. It is an estimate, not advice, and it knows nothing about your situation beyond those numbers. Rules for United States change on a published schedule; the effective date is shown on every rule-based tool.

How this is calculated

A loan payment does two jobs at once: it pays the interest that accrued this month, and it repays some principal. Because the principal shrinks, next month's interest is smaller, so more of the identical payment goes to principal. The formula answers one question. What fixed payment, repeated n times, drives the balance to exactly zero?

E = P * i * (1+i)^n / ((1+i)^n - 1)

E: The equal periodic instalment (currency)
P: Principal: the amount borrowed (currency)
i: Monthly interest rate = annual rate ÷ 12 ÷ 100 (decimal)
n: Total number of monthly instalments (months)

Worked examples

Each of these is asserted on every build. If a change to the engine ever moved one of these answers, the build would fail before the page could print it.

50k at 8.5% over 15 years

HELOC draw amount: $50,000.00
Interest rate (per year): 8.5%
Tenure: 15 years

Monthly instalment$492.37

Excel PMT(8.5%/12, 180, -50000)

Open this example

10-year repayment

HELOC draw amount: $50,000.00
Interest rate (per year): 8.5%
Tenure: 10 years

Monthly instalment$619.93

Excel PMT(8.5%/12, 120, -50000)

Open this example

zero rate

HELOC draw amount: $36,000.00
Interest rate (per year): 0%
Tenure: 15 years

Monthly instalment$200.00

i=0 branch

Open this example

Method and limits

What it assumes

Interest compounds monthly on the reducing balance.
The rate stays fixed for the whole term. Floating-rate loans reset periodically.
Processing fees, insurance and statutory charges are excluded.

What it deliberately does not model

Does not model rate resets on floating-rate loans. Most lenders hold the instalment steady and extend the term instead, so a rate rise can add years without changing what leaves your account each month.
Does not include property insurance, maintenance or association dues, or any lender fee.
Assumes every instalment is paid in full and on time.
Models the repayment phase only. During the draw period most HELOCs are interest-only, so the balance does not fall at all.
HELOC rates are almost always variable. A fixed rate here is a simplification.

Formula version 1.0.0 · definition 1.0.0 · United States · Report a problem with this calculator

Frequently asked questions

Why is my lender's payment a few dollars different from mine?: Rounding. Lenders round the payment and true up the final one against the residual balance, which is why the last month of a schedule looks lopsided. A difference of a dollar or two is normal; a difference of hundreds means a different rate, term or fee assumption.
Why is my payment almost all interest in the early years?: Interest in any month is the rate times the previous balance, and the balance starts at its maximum. On a 30-year loan at 6.9% the first year is about 86% interest. The only way to change the shape of that is to attack the balance early, which is what paying extra does.