Short answer: Borrowing $15,000 on a line of credit at 18% and paying $1,000 a month takes 18 months to pay off, with $2,121 of interest. Paying $1,500 a month instead saves $746. A 24-month term loan at 10% with a 3% fee would cost $2,062. Setting up the business? LLC vs. S-Corp: When Does an S-Corp Actually Save You Money?.
Check our math
Here is the result above, step by step, using the numbers already filled in.
- Monthly interest rate18% ÷ 12 = 1.50%
- Month 1$15,000 × 1.50% = $225 interest; $1,000 payment leaves $14,225
- Month 2$14,225 × 1.50% = $213 interest; balance $13,438
- Months to pay offrepeat until the balance reaches $0 = 18
- Total interest$2,121
- Paying $1,500 a month insteadsaves $746
- Interest-only payment to start$225/mo
How this calculator works
Lines of credit and business cards charge interest on the balance each month. The calculator applies your monthly rate to what you owe, subtracts your payment, and repeats until the balance is gone, adding any draw fee and annual fee. If your payment doesn't cover the monthly interest, the balance never goes down, and the result says so.
For cards, enter any 0% intro period: no interest is charged until it ends, and the result shows how much will still be owed when it does. Many lines of credit only require interest each month, which is why the "interest-only payment" row matters: paying just that leaves the balance where it started.
The last row prices the same amount as a 24-month term loan at 10% with a 3% fee. When payoff stretches past a year or two, a term loan with a fixed schedule is often cheaper; the business loan calculator lets you test a real offer.
Payoff time and interest on $15,000
| Monthly payment | At 12% | At 18% | At 24% |
|---|---|---|---|
| $500 | 36 mo · $2,923 | 41 mo · $5,077 | 47 mo · $8,137 |
| $750 | 23 mo · $1,820 | 24 mo · $2,967 | 26 mo · $4,348 |
| $1,000 | 17 mo · $1,334 | 18 mo · $2,121 | 19 mo · $3,012 |
| $1,500 | 11 mo · $885 | 11 mo · $1,374 | 12 mo · $1,905 |
| $2,000 | 8 mo · $672 | 9 mo · $1,032 | 9 mo · $1,417 |
Months to pay off · total interest. No intro period, draw fees or annual fees.
Worked examples
Business card with 0% for 12 months
$12,000 for new equipment on a card with 12 months at 0%, then 24%, paying $1,000 a month.
| Result | |
|---|---|
| Months to pay off | 12 |
| Balance when 0% ends | $0 |
| Total interest | $0 |
Larger line of credit with fees
$30,000 at 14% with a 2% draw fee and a $150 annual fee, paying $1,500 a month.
| Result | |
|---|---|
| Months to pay off | 23 |
| Total interest | $4,361 |
| Fees | $900 |
Card balance paid slowly
$8,000 on a business card at 27% with no intro period, paying $300 a month.
| Result | |
|---|---|
| Months to pay off | 42 |
| Total interest | $4,355 |
| Paying 50% more saves | $2,023 |
Using your result
Use revolving credit for short gaps you can see the end of: a slow month, inventory you'll sell soon, or an invoice that's late. Decide the payoff payment before you draw, and pay more whenever cash comes in.
Set a payoff date when you draw. Dividing the balance by the months until that date gives a starting payment; the calculator then shows the interest on top. Automating the payment keeps the plan on track.
If the payoff runs past two years, or you're using the line to cover regular losses, step back. The cash runway calculator shows how long cash lasts without it, and a term loan may be cheaper.
What it doesn't cover
- Rates on lines and cards are usually variable; the calculator holds the rate steady.
- It assumes one draw and fixed monthly payments.
- Card minimum payments use a typical formula; your card's may differ.
- Late fees and penalty rates aren't included.
Read more
Frequently asked questions
How long will it take to pay off $10,000 at 18%?
About 24 months at $500 a month, with $1,978 of interest.
Is a business line of credit better than a credit card?
Lines often have lower rates and suit larger, short-term needs; cards can be cheaper if you use a 0% intro period or pay in full each month. Compare the total cost for your plan.
What happens if I only pay the interest?
The balance stays where it started and you keep paying interest every month. Pay principal as well to bring the balance down.
When is a term loan better than revolving credit?
When you'll need more than a year or two to repay. A fixed schedule at a lower rate usually costs less than carrying a revolving balance.
How much should I pay each month?
At least enough to clear the balance before a 0% period ends, or within a year for a regular rate. The table shows how much faster bigger payments clear the balance and how much interest they save.
Are lines of credit variable rate?
Most are, tied to a benchmark like the prime rate, so the payment and total cost can rise. The calculator holds the rate steady; rerun it if your rate changes.
Does a business credit card affect my personal credit?
Often, yes. Most small business cards require a personal guarantee, and some issuers report to personal credit bureaus. Check the card's terms.
Do 0% intro APR business cards really cost nothing?
Only if you pay the balance before the intro period ends. Whatever is left then starts accruing interest at the regular rate.
Sources
This calculator uses only the numbers you enter; it doesn't depend on tax figures.
Updated October 2026 · By the NetTakeHome team. Estimates for planning, not tax, legal or financial advice.