Finance calculators

Line Of Credit Calculator

Updated Aug 16, 2026 By Jehan Wadia
Rate Formulas
Line of Credit Details
Your full approved limit. Interest is charged only on what you draw.
Must be greater than $0 and no more than your credit limit.
Variable LOC rates change — try the Rate Impact panel below.
Interest accrues daily; each period covers 365 ÷ frequency days.
Repayment Type
Must exceed the interest accrued each period, or the balance never falls.
Per month; spread across periods and added on top of the payment.
Used for the monthly interest estimate (365 ÷ 12 = 30.42).
$0
Slide to add extra principal on top of your fixed payment.
Traditional Loan Comparison
Pre-filled from the amount drawn — edit freely.

Enter your details to see a summary.
Line of Credit Results
Minimum Payment (interest + fees)
Payment Per Period (total outlay)
Estimated Payoff Time
Total Interest Paid
Total Cost of Borrowing
Effective Annual Cost
Daily Interest Breakdown
Step-by-Step Solution
Rate Impact (variable-rate risk)
Scenario Annual Rate Total Interest Payoff Time
Line of Credit vs. Traditional Loan
Line of Credit
Payment Per Period
Total Interest Paid
Total Cost of Borrowing
Payoff Timeline
Effective Annual Cost
Traditional Loan
Payment Per Period
Total Interest Paid
Total Cost of Borrowing
Payoff Timeline
Effective Annual Cost
Chart 1 — Interest vs. Principal vs. Fees
Line of Credit
Traditional Loan
Chart 2 — Remaining Balance Over Time
Line of credit = solid line; traditional loan = dashed line.
Chart 3 — Payment Frequency Impact on Total Interest
Each frequency uses the same total amount paid per year; your current selection is marked “(selected)”.
Repayment Schedule

Introduction

A line of credit lets you borrow money up to a set limit. You only pay interest on the part you use, not the whole limit. This Line of Credit Calculator shows you what that borrowing really costs.

Type in your credit limit, how much you have drawn, and your interest rate. Pick how often you pay: weekly, bi-weekly, semi-monthly, or monthly. Then choose to make fixed payments that lower your balance, or interest-only payments that keep the balance the same.

The calculator gives you your minimum payment, payoff time, total interest, and total cost of borrowing. It also breaks down your daily interest, shows each step of the math, and builds a full payment schedule.

You can compare your line of credit to a regular loan side by side. A slider lets you test extra payments and see how much interest and time you save. Charts show your balance dropping over time and how payment frequency changes your interest.

Rates on a line of credit can go up. The Rate Impact table shows what happens to your total interest if your rate rises by 1% or 2%. Use this tool before you borrow so there are no surprises later.

How to use our Line of Credit Calculator

Enter your credit limit, how much you have drawn, your interest rate, and how you plan to pay it back. The calculator shows your minimum payment, payoff time, total interest, total cost of borrowing, a full repayment schedule, and how a line of credit compares to a regular loan.

Total Credit Limit: Type the full amount your lender approved you for. You only pay interest on what you use. If you want to see how your balance stacks up against your limit, try the Credit Utilization Calculator.

Amount Currently Drawn: Type how much you have borrowed right now. It must be more than $0 and not more than your limit.

Annual Interest Rate (AIR): Enter your yearly rate as a percent, like 7.5. Most line of credit rates can change over time. Not sure what rate you are really paying? The APR Calculator and the Effective Interest Rate Calculator can help.

Payment Frequency: Pick how often you pay: monthly, semi-monthly, bi-weekly, or weekly. Interest builds daily, so this changes your cost.

Repayment Type: Choose "Fixed Repayment" to pay principal plus interest, or "Interest-Only" to pay just the minimum payment each period.

Fixed Repayment Amount: Enter how much you will pay each period. It must be more than the interest that builds up, or your balance will never drop.

Interest-Only Period: If you chose interest-only, enter how many months you will pay interest before you repay the full principal in one lump sum. See the Balloon Payment Calculator to plan for that final payment.

Optional Monthly Fees / Insurance: Enter any monthly fee your lender charges. Leave it at 0 if you have none.

Avg. Days in Billing Cycle: Enter the number of days in your billing cycle. Most people use 30.42, which is 365 days divided by 12 months.

"What-If" Extra Payment Per Period: Slide this to add extra money to each payment. The tool shows how much interest and time you save. For a full debt plan, pair it with the Debt Payoff Calculator.

Compare with a Traditional Loan: Turn this switch on to see a side-by-side match up with a normal term loan. You can also run the numbers in our Loan Comparison Calculator.

Loan Principal: Enter the loan amount you want to compare. It fills in from your drawn amount, but you can change it.

Loan Annual Interest Rate: Enter the yearly rate on the loan as a percent. Loan rates are often higher than line of credit rates.

Loan Term: Enter how long the loan lasts, then pick months or years.

Loan Payment Frequency: Pick how often you would pay the loan back. The Loan Payment Calculator breaks down a single fixed payment in more detail.

Click Calculate to see your results, charts, and schedule. Click Reset to start over with the default numbers.

What Is a Line of Credit?

A line of credit (LOC) is a pool of money a bank lets you borrow from. You get a credit limit, like $25,000. You can take out as much or as little as you want, up to that limit. You only pay interest on the part you actually take out, not the whole limit. When you pay money back, that amount is free to borrow again. That is why a line of credit is called revolving credit, the same structure used by a credit card (see the Credit Card Interest Calculator) or a HELOC secured by your home.

How Line of Credit Interest Works

Most lines of credit charge daily interest. The bank takes your yearly rate, splits it over 365 days, and charges that small amount on your balance each day. So a smaller balance means less interest, and paying early in the month saves you money.

The math looks like this:

  • Daily rate = yearly rate ÷ 365
  • Daily interest = balance × daily rate
  • Monthly interest = daily interest × days in the billing cycle (about 30.42)

Example: $10,000 drawn at 7.5% costs about $2.05 a day, or close to $62 a month in interest. Our Monthly Interest Calculator and Daily Compound Interest Calculator show the same idea from other angles.

Minimum Payment vs. Fixed Payment

Your minimum payment is usually just the interest (plus any fees). It keeps your account in good standing, but your balance never goes down. This is called interest-only.

A fixed payment is a set dollar amount you pay each period. Part of it covers interest, and the rest cuts down the principal. Your payment must be bigger than the interest that builds up each period, or your balance will never shrink. The Loan Payoff Calculator shows how a steady payment closes out a balance.

Variable Rates: The Big Risk

Most lines of credit use a variable rate. It moves up and down with the lender's prime rate. If rates rise 1% or 2%, your interest cost rises too, and it takes longer to pay off the balance if your payment stays the same. Always check what happens to your budget if rates climb, and keep an eye on your debt-to-income ratio and your monthly budget.

Line of Credit vs. Traditional Loan

  • Line of credit: Borrow again and again, flexible payments, rate usually variable, no set end date. Best for uneven costs like home repairs or a business cash gap (see the Business Loan Calculator).
  • Traditional loan: One lump sum, fixed payment, fixed rate, set end date. Best when you know the exact amount you need and want a clear payoff date. Run it through the Loan Calculator or the Personal Loan Calculator.

A line of credit often has a lower rate, but because there is no deadline, many people carry the balance for years and pay more interest in the end. A loan forces you to finish. If you are using a line of credit to clear other debts, compare it with the Debt Consolidation Calculator and the Balance Transfer Calculator.

Ways to Pay Less Interest

  • Pay more than the minimum. Every extra dollar goes straight to principal. The Debt Avalanche Calculator and Debt Snowball Calculator help you decide which balance to hit first.
  • Pay more often. Weekly or bi-weekly payments cut the balance sooner, so less daily interest builds up.
  • Only draw what you truly need.
  • Count monthly fees or insurance as part of the real cost.
  • Keep a cash cushion so you do not have to draw again; the Emergency Fund Calculator shows how much to set aside.

Words to Know

  • Credit limit: The most you are allowed to borrow.
  • Draw: Money you take out of the line.
  • Principal: The amount you borrowed, before interest. See the Loan Interest Calculator.
  • Total cost of borrowing: Principal + interest + fees.
  • Effective annual cost: The true yearly cost once interest, fees, and payment timing are all counted. Related to APY and the internal rate of return.
  • Balloon payment: One large payment of the full principal at the end of an interest-only period.

Formulas used

Daily periodic interest rate
r_d = \frac{\text{AIR}}{365}
Periodic interest rate (days per period)
r_p = r_d \times \frac{365}{m}
Minimum (interest-only) payment per period
\text{Min Payment} = B \times r_p + \frac{F_{\text{monthly}} \times 12}{m}
Per-period amortization of the line of credit
I_t = B_{t-1} \times r_p, \quad P_t = \text{Pmt} - I_t, \quad B_t = B_{t-1} - P_t
Total cost of borrowing
\text{Total Cost} = \text{Principal} + \sum I_t + \sum \text{Fees}
Traditional loan payment per period
\text{Pmt} = \frac{P \cdot r}{1 - (1 + r)^{-n}}, \quad r = \frac{\text{AIR}}{m}
Effective annual cost from periodic IRR
\text{EAC} = \left[(1 + i)^{m} - 1\right] \times 100\%, \quad \text{where} \sum_{t=0}^{n} \frac{CF_t}{(1+i)^t} = 0
Monthly interest estimate from daily accrual
I_{\text{month}} = B \times r_d \times d_{\text{cycle}}

Frequently asked questions

Why do I get an error saying my payment is too low?

Your fixed payment must be bigger than the interest that builds up each period. If it is not, the interest eats the whole payment and your balance never drops.

The error message shows the exact interest amount for your period. Enter a payment above that number.

Does my credit limit change how much interest I pay?

No. Interest is charged only on the amount you draw, not your limit.

The calculator uses the limit as a cap. Your drawn amount cannot be higher than it.

What is the Effective Annual Cost in my results?

It is the true yearly cost of your borrowing once interest, fees, and payment timing are all counted.

It is often higher than your stated rate because fees and daily interest add up. Use it to compare two options fairly.

Why is the Effective Annual Cost higher than my interest rate?

Two reasons:

  • Interest is charged more than once a year, so it stacks up.
  • Any monthly fee you enter is counted as a real cost of borrowing.

Set fees to $0 and the gap gets much smaller.

Does the calculator assume I take out more money later?

No. It assumes you make one draw and pay it down. It does not add new draws.

If you plan to borrow again, run the tool a second time with your new balance.

What does the break-even point mean in the comparison?

It is the month when the line of credit and the loan have cost you about the same in interest and fees.

Before that month one option is cheaper. After it, the other one wins. It helps if you are not sure how long you will keep the debt.

Why does the Rate Impact table only go up 2%?

Most variable rates move in small steps, so +1% and +2% cover the common cases.

If you want a bigger jump, just type a higher rate in the Annual Interest Rate box and check the results.

Why does paying weekly cost less interest than paying monthly?

Interest builds every day on your balance. Paying weekly drops the balance sooner, so fewer days of interest pile up.

Chart 3 shows this. It keeps your yearly total the same and only changes how often you pay.

What does the balloon tag mean in the schedule?

It marks the last payment in Interest-Only mode. That row includes the full principal in one lump sum.

Make sure you have a plan to cover that big payment before you pick this option.

Does unpaid interest get added to my balance?

No. This tool assumes you pay all the interest each period, so interest is never charged on interest.

Real lenders may add unpaid interest to your balance if you skip a payment. That would cost more.

Can I use this tool for a HELOC or a business line of credit?

Yes. The math is the same for any revolving line that charges daily interest.

Just enter your own limit, drawn amount, rate, and fees.

Why did my loan principal fill in by itself?

It copies your drawn amount so the comparison starts fair, matching dollar for dollar.

Once you type in that box, it stops copying and keeps your number.

What should I put for days in the billing cycle?

Use 30.42 if you are not sure. That is 365 divided by 12.

If your statement always covers 30 or 31 days, enter that instead. It only changes the monthly interest estimate.

Why does my payoff time show a decimal, like 22.4 months?

Payments do not always land on a clean month, mostly with weekly or bi-weekly plans.

The number of payments is exact. The month figure is just those payments turned into months.

Does the extra payment slider work with interest-only mode?

No. Interest-only payments never touch principal, so extra money has nothing to shrink.

Switch to Fixed Repayment to use the slider and see your savings.

Is the last payment always the same size?

No. The final payment is usually smaller. It only covers the leftover balance plus that period's interest.

You can see the exact amount in the last row of the schedule.

Why is the traditional loan cheaper in some results?

A loan has a set end date, so you are forced to pay it off. A line of credit with a small payment can drag on for years.

Raise your fixed payment and the line of credit often wins again.

Does the total cost of borrowing include the money I borrowed?

Yes. It is principal plus interest plus fees.

If you only want the cost of the debt itself, look at Total Interest Paid instead.

Are the results exact to the penny?

They are close, but not a promise. Lenders round differently, use different day counts, and may add fees this tool does not know about.

Use the numbers to plan and compare, then confirm with your lender.

How do I see all my payments instead of just 12?

Click View Full Repayment Schedule, then click Show all.

You can also click Show 12 more to add a year at a time.