What will my line of credit cost?
Type what you owe on the line of credit and its APR. The line of credit calculator gives the interest-only payment while the draw period lasts and the level payment over the repayment term, or how many months a fixed payment takes to clear the balance, with the total interest and a payment schedule.
- Monthly payment
- $415.17
Your line of credit payment is $415.17 a month, with $6,710.03 of interest in all.
- Interest-only payment
- $150.00
- Months to pay off
- 72
- Total interest
- $6,710.03
- Total paid
- $26,710.03
- Amount drawn
- $20,000.00
- Months
- 72
Monthly payment: $415.17. Your line of credit payment is $415.17 a month, with $6,710.03 of interest in all.
How does the balance fall?
Where does each year’s money go?
What does every payment look like?
The results are estimates for information only. They are not financial, tax, or legal advice. Check the numbers with your lender or a qualified professional before you decide. Terms of use
How to calculate
Works out the monthly payment on a line of credit balance: interest-only in the draw period, then level payments over the repayment term, or how long a fixed payment takes to clear it, with the total interest.
Example with the default inputs (Amount drawn $20,000.00, Interest rate (APR) 9%, Repay by Draw, then term, Interest-only months 12, Repayment months 60): Your line of credit payment is $415.17 a month, with $6,710.03 of interest in all.
Method: r = APR ÷ 12; draw months pay B × r; then the level payment B × r ÷ (1 − (1 + r)^−term) (B ÷ term at 0%); a fixed payment P clears the balance in −ln(1 − rB/P) ÷ ln(1 + r) months.
- Interest each month is the APR ÷ 12 on the balance. Lenders that charge a daily rate on the daily balance give slightly different amounts.
- You draw nothing more after today, and the rate stays the same. Many lines of credit have variable rates.
- Payments are made at the end of each month; the last payment clears what is left. Fees are not included.
Worked examples
Each example is checked against the calculator on every build.
- Amount drawn $12,000.00, Interest rate (APR) 0%, Repay by Draw, then term, Interest-only months 0, Repayment months 12 gives Monthly payment $1,000.00, Total interest $0.00, Months to pay off 12.Source: Consumer Financial Protection Bureau, What is a home equity line of credit (HELOC)? (you can borrow up to the limit during the draw period; then the repayment period starts, the lender sets a schedule to repay the full balance, and payments often go up), https://www.consumerfinance.gov/ask-cfpb/what-is-a-home-equity-line-of-credit-heloc-en-107/ (retrieved 2026-10-02)
- Amount drawn $20,000.00, Interest rate (APR) 9%, Repay by Draw, then term, Interest-only months 12, Repayment months 60 gives Interest-only payment $150.00, Monthly payment $415.17, Months to pay off 72, Total interest $6,710.03.Source: Consumer Financial Protection Bureau, What is a home equity line of credit (HELOC)? (you can borrow up to the limit during the draw period; then the repayment period starts, the lender sets a schedule to repay the full balance, and payments often go up), https://www.consumerfinance.gov/ask-cfpb/what-is-a-home-equity-line-of-credit-heloc-en-107/ (retrieved 2026-10-02); Consumer Financial Protection Bureau, Regulation Z, 12 CFR 1026.7 Periodic statement (the statement discloses each periodic rate that may be used to compute the finance charge), https://www.consumerfinance.gov/rules-policy/regulations/1026/7/ (retrieved 2026-10-02)
- Amount drawn $10,000.00, Interest rate (APR) 12%, Repay by Fixed payment, Monthly payment $500.00 gives Months to pay off 23, Total interest $1,213.48.Source: Consumer Financial Protection Bureau, Regulation Z, 12 CFR 1026.7 Periodic statement (the statement discloses each periodic rate that may be used to compute the finance charge), https://www.consumerfinance.gov/rules-policy/regulations/1026/7/ (retrieved 2026-10-02)
How it works
The monthly rate is r = APR ÷ 12 (as a decimal: 9% gives 0.0075). B is the amount drawn. Each month the interest is the balance × r, the payment is made at the end of the month, and principal = payment − interest.
Draw, then term. With d interest-only months and a repayment term of t months:
- interest-only payment = B × r, paid for the first d months (the balance stays B)
- monthly payment = B × r ÷ (1 − (1 + r)^−t), or B ÷ t when the APR is 0, for the next t months; the last of them pays whatever is left, so the balance ends at exactly 0
- months to pay off = d + t
Fixed payment. With a payment P each month:
- P must be more than B × r, the first month’s interest
- the balance is gone after −ln(1 − rB ÷ P) ÷ ln(1 + r) months (B ÷ P at 0%), rounded up to whole payments; the last payment is smaller and clears the balance
- more than 600 months (50 years) gives no answer
In both: total interest adds every month’s interest; total paid = B + total interest.
Rules
- The amount drawn is from $0.01 to $10⁸; the APR from 0% to 100%; interest-only months from 0 to 360; repayment months from 1 to 480; the fixed payment from $0.01 to $10⁸.
- Amounts are not rounded to the cent between months.
Output format. Money to the cent; months as a whole number.
Worked examples by hand
$12,000 at 0% over 12 months, no draw period. 12,000 ÷ 12 = $1,000 a month, $0 interest.
$20,000 at 9%, 12 interest-only months, then 60 months. r = 0.0075. Interest-only: 20,000 × 0.0075 = $150 a month, $1,800 in the year. Then 20,000 × 0.0075 ÷ (1 − 1.0075^−60) = $415.17 a month. Total interest = 1,800 + 60 × 415.17 − 20,000 = $6,710.03; 72 months.
$10,000 at 12% paid at $500 a month. r = 0.01. −ln(1 − 0.01 × 10,000 ÷ 500) ÷ ln 1.01 = −ln 0.8 ÷ ln 1.01 = 22.43, so 23 payments, the last one smaller. Adding each month’s interest gives $1,213.48.
Other questions people ask
How is the interest on a line of credit worked out?
Each month the interest is the balance times the APR ÷ 12. On $20,000 at 9%, that is 20,000 × 0.09 ÷ 12 = $150 a month. Many lenders use a daily rate on the daily balance instead, which gives slightly different amounts.
What is an interest-only payment?
During the draw period many lines let you pay only the interest, so the balance does not fall. On $20,000 at 9% it is $150 a month, and after a year you still owe $20,000. Check your agreement for the minimum payment your lender asks for.
What happens when the draw period ends?
The repayment period starts: you can no longer borrow, and the balance is paid off in level payments that include principal. $20,000 at 9% over 60 months is about $415.17 a month, much more than the $150 interest-only payment.
How long will a fixed payment take to pay off my line of credit?
With balance B, monthly rate r and payment P, the months are −ln(1 − rB ÷ P) ÷ ln(1 + r). $10,000 at 12% paid at $500 a month takes 22.4 months, so 23 payments, with about $1,213 of interest. A payment at or below the first month’s interest never clears the balance.
How does a line of credit differ from a loan?
A loan pays out once and is repaid on a fixed schedule. A line of credit lets you borrow up to a limit, repay and borrow again during the draw period, and often has a variable rate. This calculator looks at the balance you owe now, as if you draw nothing more.