What Is a Line of Credit (LOC)? Types and How It Works

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A line of credit (LOC) is a borrowing arrangement in which a lender approves a maximum amount, the credit limit, and lets the borrower draw funds from it as needed rather than receiving a lump sum. Interest accrues only on the amount actually drawn. On a revolving line, any principal you repay becomes available to borrow again. Banks, credit unions and other lenders offer lines of credit to individuals and businesses. The lender sets the limit based on the borrower’s creditworthiness and, for secured lines, the value of the collateral.

What Is a Line of Credit (LOC)?

“LOC” stands for line of credit. People also say “credit line,” especially for the limit itself, as in “a $10,000 credit line.” A conventional loan joins approval and borrowing: you receive the full amount at once, and interest starts on the full sum. A line of credit separates them. Approval sets a ceiling, and you borrow later, in whatever amounts and at whatever times you choose, within the limit and the contract terms. That makes it a standby source of cash for expenses of uncertain timing or size. It also makes overspending easy.

Several terms come up constantly:

• Credit limit (credit line): the maximum the lender will let you owe at one time.
• Outstanding balance: what you currently owe, including principal drawn and any unpaid interest and fees.
• Available credit: the credit limit minus the outstanding balance.
• Draw: each time you take money from the line.
• Draw period: on some lines, especially HELOCs, the window during which you can borrow. After it ends, a repayment period begins.

How a Line of Credit Works

You apply, and the lender reviews your credit history, income, existing debts and, for a secured line, your collateral. If you are approved, the lender sets a limit, an interest rate (usually variable and tied to a benchmark such as the prime rate plus a margin) and repayment terms.

Once the line is open, you can draw funds by several methods. Depending on the lender, these include transfers to a checking account, special checks, a card linked to the line, or a request at a branch. Each draw raises your balance and lowers your available credit. Each payment toward principal does the reverse.

Repayment is flexible. You must make at least the minimum payment each billing cycle, which on many lines covers the accrued interest and sometimes a portion of principal. You can pay more, or clear the balance, whenever you like. With no balance you usually pay no interest, although some lines charge an annual fee, a maintenance fee or a fee per draw.

Interpreting a Line of Credit

Interest on most lines is calculated on the daily or average daily balance:

Interest for the cycle = average daily balance × (APR ÷ 365) × days in the cycle

The APR on a variable line can change over the life of the account. When the benchmark rises, the cost of the balance you already carry rises with it, not only the cost of new draws.

Utilization is the share of your limit in use:

Utilization = outstanding balance ÷ credit limit

Credit scoring models look at this ratio for revolving accounts, which is why a line’s limit and balance affect your score as well as your budget.

Available credit is the limit minus the balance. Pending draws or accrued interest can reduce it before they appear as posted transactions.

Example of a Line of Credit

Hypothetical example for illustration only; the rates and amounts are not any lender’s terms.

Maria opens an unsecured personal line of credit with a $20,000 limit at a variable 12% APR. She doesn’t draw anything for the first two months, so she owes no interest.

In month three, she draws $5,000 to cover a car repair and a medical bill. Her available credit falls to $15,000. If the $5,000 stays outstanding for a 30-day cycle, interest is about:

$5,000 × (0.12 ÷ 365) × 30 ≈ $49.32

She pays $3,049.32: the interest plus $3,000 of principal. Her balance drops to $2,000, and her available credit returns to $18,000. Her utilization goes from 25% ($5,000 ÷ $20,000) to 10%.

Now assume the benchmark rate rises and her APR resets to 13.5%. The same $2,000 balance now costs roughly $22.19 per 30-day cycle instead of about $19.73. Nothing about her borrowing changed; the variable rate did. A fixed-rate installment loan would not have moved.

A $20,000 personal loan taken up front “just in case” would have accrued interest on the full amount from day one, even though Maria needed $5,000 at most.

Secured vs. Unsecured Lines of Credit

An unsecured line is backed only by your promise to repay. If you default, the lender can pursue collection, report the delinquency and sue, but it has no lien to enforce. To offset that risk, lenders set stricter credit requirements, lower limits and higher rates. Personal lines of credit are usually unsecured. Credit cards are also unsecured revolving credit: the card’s limit is the line, and their high APRs reflect the lack of collateral. Unlike cards, personal and home equity lines usually let you draw cash directly at lower rates than card cash advances.

A secured line is backed by collateral: home equity, a savings account or certificate of deposit, or an investment portfolio. If you stop paying, the lender can take or sell the collateral to recover what it is owed. Lower risk for the lender usually means a higher limit and a lower rate for the borrower. The trade-off is that the asset itself is at risk. With a HELOC, that asset is your home.

Revolving vs. Non-Revolving Lines of Credit

A revolving line of credit, also called open-end credit, can be drawn, repaid and drawn again for as long as the account stays open and in good standing. Personal lines, HELOCs during their draw period, business lines and credit cards all work this way.

A non-revolving line allows draws over time up to a limit, but payments do not restore available credit. Draw $6,000 from a $10,000 non-revolving line and you have $4,000 left, even after repaying the $6,000. Once the balance is paid in full, the account closes. Some construction and project financing works this way: funds are drawn in stages as work progresses, and repayment winds the facility down.

Both types differ from installment loans such as mortgages, auto loans and most personal loans. With an installment loan, you receive a fixed amount once and repay it on a set schedule. To borrow more, you must apply again.

On the business side, a transaction-based line of credit is approved for a specific purchase, contract or shipment rather than general working capital. Funds can typically be used only for that purpose, and the line is repaid when the transaction completes, often from its proceeds. That puts it closer to project financing than to an open-ended revolving line.

Types of Lines of Credit

Personal Line of Credit

A personal line of credit is usually unsecured and revolving. Lenders typically look for a clean credit history with no defaults, steady income and a credit score often around 670 or higher. Savings or assets such as CDs or stocks can strengthen an application, though collateral is not required.

Overdraft lines link a personal line to your checking account. When a payment would overdraw the account, the shortfall is covered by a draw on the line instead of being declined or returned. The covered amount accrues interest until you repay it.

Home Equity Line of Credit (HELOC)

A HELOC is the most common secured line of credit. It is backed by your home equity: the home’s market value minus what you owe on it. Lenders usually cap your existing mortgage plus the HELOC at a combined loan-to-value limit, commonly 75% to 80% of the home’s value.

Hypothetical calculation: a home appraised at $400,000 with an 80% combined limit supports $320,000 of total debt. With a $250,000 mortgage balance, the maximum HELOC would be $320,000 − $250,000 = $70,000, subject to the lender’s other underwriting criteria.

HELOCs have two phases. During the draw period, often 10 years, you can borrow, repay and borrow again, and many plans require only interest payments. When the draw period ends, you can no longer borrow. The balance then either becomes due or converts to a repayment period with principal and interest payments. That switch can sharply increase the monthly payment for a borrower who paid only interest during the draw period. HELOCs also usually involve closing costs, including an appraisal of the property.

On taxes: under the Tax Cuts and Jobs Act of 2017, interest on a HELOC is deductible on a U.S. federal return only if the funds are used to buy, build or substantially improve the home that secures the line, and only within the overall mortgage interest limits. Interest on a HELOC used to pay off credit cards or fund a vacation is not deductible.

Business Line of Credit

A business line of credit lets a company borrow as needed for working capital, inventory, payroll gaps or seasonal swings instead of taking a fixed term loan. The lender evaluates the business’s revenue, profitability, cash flow, assets and risk. The line may be unsecured or secured by receivables, inventory, equipment or a personal guarantee from the owner, and rates are generally variable. Some business lines must be paid down to zero for a period each year, which shows the lender the line funds short-term needs rather than permanent capital.

Demand Line of Credit

A demand line can be secured or unsecured, and the lender can call the outstanding balance due at any time, not only on default. Until the lender calls it, the borrower can draw up to the limit, and payments may be interest-only or interest plus principal depending on the agreement. Demand lines are not widely used by consumers, and the call feature makes them unpredictable for the borrower.

Securities-Backed Line of Credit (SBLOC)

An SBLOC is a secured demand line backed by the securities in a brokerage account. The amount you can borrow depends on the type and value of the holdings, and it typically ranges from 50% to 95% of their value. Cash equivalents and high-grade bonds support higher percentages than individual stocks do.

SBLOCs are non-purpose loans: the money cannot be used to buy or carry securities, though almost any other use is allowed. Payments are usually monthly and interest-only until you repay or the lender demands repayment. A demand can come if the portfolio falls far enough relative to the balance. The lender can then require you to deposit cash or securities or repay part of the balance, or it can sell holdings, possibly at a bad time and with tax consequences.

How to Use a Line of Credit

A line of credit fits needs that are uncertain in timing or size, or that recur:

• Emergency backup: an unexpected repair or medical bill, without having to sell investments.
• Smoothing cash flow: freelancers, commission earners and seasonal businesses bridging the gap between expenses and income.
• Staged projects: a renovation paid as invoices arrive, especially through a HELOC, where interest may be deductible if the rules above are met.
• Overdraft protection: covering a checking shortfall.
• Short-term bridge financing: funding a purchase that will be repaid from an expected inflow, such as a bonus or a sale.

It is a poor fit for a single large purchase paid off over many years. A fixed-rate installment loan gives a predictable payment and a definite end date for that kind of expense.

Limitations of a Line of Credit

• Variable rates: nearly all lines float, so payments can rise without any new borrowing, and pricing varies widely between lenders.
• Higher cost when unsecured: unsecured lines carry higher rates and tougher qualification standards than secured ones.
• Collateral at risk: default on a HELOC can lead to foreclosure; a portfolio decline can trigger a call on an SBLOC.
• Fees and penalties: annual, draw, late and over-limit fees can apply. Personal lines don’t carry all the consumer protections that federal law gives credit cards, so penalties can be steep.
• Overspending: constant access to cash makes it easy to carry a balance indefinitely while paying mostly interest.
• Lender discretion: lenders can typically reduce the limit, freeze further draws or decline to renew a line, for example after a drop in your credit score or, for a HELOC, a significant decline in the home’s value. Any balance already owed remains due under the account’s repayment terms.

How a Line of Credit Affects Your Credit Score

Applying usually triggers a hard inquiry, which can lower your score slightly for a short time. After that, the line affects your score mainly through payment history and, for revolving accounts, utilization. A widely cited guideline is to keep utilization below 30%, and lower is better. Maria’s $5,000 draw was 25% of her $20,000 limit, but the same draw on an $8,000 line would be 62.5%. Late payments do the most lasting damage. Closing an unused revolving line reduces your total available credit and can raise your overall utilization.

The Bottom Line

A line of credit suits borrowers facing costs of uncertain timing or size, such as emergencies, staged renovations or uneven income. It works best for short-term needs that get repaid, since variable rates, fees and easy access can keep a balance growing. A single large purchase repaid over many years usually fits better with a fixed-rate installment loan, and secured lines put the home or portfolio at risk.