Business Line of Credit Cost Calculator

Read the business line of credit calculator result

A business credit line’s ending balance doesn’t show how much was borrowed throughout the billing cycle. A draw early in the period can create more interest than the same draw near the end. Some agreements also charge for unused commitment, making the available portion of the line relevant to the fee calculation.

This calculator follows one opening balance, one additional draw, and one principal repayment through a cycle of up to 62 days. It calculates interest on drawn principal, an optional annual fee on unused commitment, and one additional flat cycle charge. The output includes average balances and a daily step chart with an interval-level reconciliation.

It models entered terms, not a loan quote or borrowing approval. The rate, unused fee, and limit shown initially are illustrations. Your agreement determines whether these charges exist, how balances are measured, and when payments must be made.

Business line of credit: separate the credit limit from drawn principal

The credit limit is the total committed amount assumed available during the cycle. Opening principal is the amount already drawn before the first day’s events. The additional draw increases principal, while the entered repayment reduces principal. Neither event changes the committed limit in this model.

Interest is calculated on drawn balances. For example, Bank of America’s own business-line FAQ describes interest applying to amounts drawn under that product. That doesn’t establish every charge on every business line. A separate commitment fee can apply to unused availability if the particular agreement provides for it.

A 2019 SEC-filed credit agreement amendment provides a concrete example of a contractual fee based on daily unused commitment and an actual/360 convention. It’s cited to show the type of term that can exist, not as a current market rate or a rule that applies to your account.

If your contract has no unused-line fee, enter zero for that rate. Don’t add one simply because the calculator provides the field. A standby letter, borrowing-base restriction, reserve, or other reduction in availability isn’t automatically modeled by the difference between limit and principal.

Enter posting days and the day-count basis

Cycle days are numbered from one through the selected cycle length. A draw or repayment takes effect at the start of its posting day, and that day’s closing principal is used for the daily charge. Thus, a draw on day 11 of a 30-day cycle affects twenty days, including day 11.

Use the date the event is effective under the agreement, rather than assuming a payment instruction immediately reduces the balance. The business line of credit calculator doesn’t model processing delays, weekends, or banking cutoffs. If the actual agreement uses a different balance convention, the estimate may not match the statement.

The annual denominator can be 365 or 360. Both choices use the actual cycle days entered. Actual/360 isn’t the same as a 30/360 calendar method; selecting 360 doesn’t alter the number of days in the cycle.

A nonzero draw or repayment must fall within the cycle. Zero-amount events have no balance effect. If draw and repayment occur on the same day, the business line of credit calculator applies their net change at the start of that day. Intraday peaks and the order of transactions within that day are outside the model.

How the business line of credit calculator works

Add the principal balance for every day to obtain drawn balance-days. Divide by cycle days to find average drawn balance. Unused commitment each day equals the credit limit minus that day’s drawn principal; summing those amounts produces unused balance-days.

Interest charge = drawn balance-days × annual interest rate ÷ day basis. Use the annual rate as a decimal. Unused commitment fee = unused balance-days × annual unused-fee rate ÷ day basis. Total cycle charges add those two amounts and the entered flat fee once.

Interest and fees are assumed paid separately at cycle-end. They aren’t added to principal during the cycle, so they don’t generate additional interest in this calculation. Closing principal reflects only the opening balance, draw, and principal repayment.

The model checks that daily principal stays between zero and the committed limit. A repayment larger than the available principal isn’t treated as a deposit account credit, and a draw above the limit isn’t silently approved. These are mathematical constraints, not a lender’s availability decision.

Business line of credit calculator example: a draw and a repayment in a 30-day cycle

Assume a $50,000 line with $10,000 drawn at the opening. Draw another $15,000 on day 11, then repay $5,000 of principal on day 21. Use a 12% annual interest rate, a 0.5% annual unused-commitment fee, a $25 flat cycle fee, and an actual/365 basis.

Drawn balance-days total $550,000-days: $100,000 for the first interval, $250,000 for the second, and $200,000 for the third. Average drawn principal is $18,333.33. Unused balance-days total $950,000-days, giving average unused commitment of $31,666.67.

Interest is $550,000 × 12% ÷ 365 = $180.82 after display rounding. The unused fee is $950,000 × 0.5% ÷ 365 = $13.01. Adding the $25 flat fee gives total cycle charges of $218.84 using unrounded intermediate amounts.

Closing principal is $20,000. The $218.84 of charges is a separate cycle-end cash requirement under this convention; it does not make closing principal $20,218.84. If your agreement capitalizes charges, a future balance model must reflect that different treatment.

Test an earlier principal repayment

Move the $5,000 repayment from day 21 to day 11, leaving the draw and all other terms unchanged. The same-day net increase is $10,000, so principal is $10,000 for ten days and $20,000 for twenty days. Closing principal remains $20,000.

Drawn balance-days fall to $500,000-days. Interest falls to $164.38, while the unused fee rises to $13.70 because more of the commitment remains unused. Total charges become $203.08, a reduction of about $15.75.

The example shows why looking only at closing principal can miss a meaningful timing difference. It also shows why a repayment can reduce interest while increasing a contract’s unused fee. Under these entered rates, the interest reduction is larger. That relationship depends on the actual fee and interest assumptions.

Test the denominator and fee scope separately

Restore the original posting days and switch the annual basis from 365 to 360. Interest becomes $183.33, the unused fee $13.19, and total charges $221.53. The principal balances, posting dates, and thirty actual days are unchanged.

In another separate run, retain actual/365 and set the unused fee to zero. Total charges become $205.82, consisting of interest plus the $25 flat fee. These are alternative contract scenarios; don’t choose the cheaper basis or omit a fee unless that treatment matches the agreement being evaluated.

The total charge is a dollar estimate for this cycle. It isn’t a disclosed APR or a full-year borrowing cost. A fixed fee can have a large effect on a short or lightly used cycle, and repeating this cycle twelve times would assume a borrowing pattern that the business line of credit calculator hasn’t established.

Reconcile the estimate with a statement

Collect the opening principal, effective event dates, rate, day-count convention, and fee terms. Confirm whether the unused-fee definition includes other commitments beyond drawn principal. Check for minimum charges, rate resets, fee tiers, or separate annual renewal charges that can’t be represented by one constant rate and flat cycle amount.

Compare the interval table with your statement’s balance history. A one-day difference in when a draw or repayment becomes effective changes balance-days even if the cash amounts match. A chart step in the wrong place often reveals a timing mismatch more clearly than a small difference in the final fee total.

Use the invoice delay cost calculator when examining a single delayed collection and the early payment discount calculator when comparing a supplier discount with a simple funding cost. This credit-line tool adds the actual balance pattern and unused-fee assumption for a different question.

The cash runway calculator can help examine a simplified operating reserve, but an approved limit isn’t the same as cash already on hand. This calculator doesn’t determine borrowing-base eligibility, continued availability, covenant compliance, or renewal.

Business line of credit calculator questions

Why does the unused fee increase after repayment?

Repayment increases the difference between the committed limit and drawn principal. If the contract charges the entered fee on that unused amount, its fee base rises. The interest base falls at the same time.

Are charges compounded during the cycle?

No. The model applies simple daily charges to principal and assumes interest and fees are paid separately at the end. It doesn’t capitalize them.

Can I enter several draws and repayments?

This version accepts one additional draw and one principal repayment. A more active account needs a full daily ledger or a model that accepts every event.

Does a valid result mean the bank permits the draw?

No. It means the entered daily balances fit the numerical limit. Actual borrowing permission and available credit depend on the agreement and lender.