Loan Calculator
Calculate your monthly payment, total interest, and payoff schedule for any personal or installment loan. Add extra payments to see how much interest you can save, or switch modes to find how much you can borrow for a payment you can afford.
| Period | Payment | Principal | Interest | Balance |
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How to Use the Loan Calculator
This loan calculator helps you estimate the payment on any personal, installment, or fixed-rate loan. Enter your loan amount, annual interest rate, and repayment term to instantly see your payment and total cost of borrowing. Use the extra payment field to see how much interest you save by paying more each period.
Bi-weekly vs Monthly Payments
Choosing bi-weekly payments instead of monthly means you make 26 half-payments per year — equivalent to 13 full monthly payments instead of 12. This one extra payment per year can shorten a 3-year loan by about 2 months and save meaningful interest over the life of the loan.
The Loan Payment Formula
Monthly payments use the amortization formula: M = P × r(1+r)ⁿ / [(1+r)ⁿ−1], where P = principal, r = monthly interest rate (APR ÷ 12), and n = number of payments. For bi-weekly, r = APR ÷ 26.
How Loan Term Affects Total Cost
The longer your loan term, the lower your monthly payment — but the more total interest you pay. On a $15,000 loan at 10.5%: a 36-month term costs about $2,550 total in interest; a 60-month term costs about $4,350. Choosing the longer term saves ~$165/month but costs ~$1,790 more overall.
Tips to Get the Best Loan Rate
- Check your credit score before applying — rates are tier-based on credit
- Compare APRs from at least 3 lenders (banks, credit unions, online lenders)
- Credit unions often offer rates 1–3% lower than banks
- Consider a shorter term if you can afford the higher payment — you'll save significantly on interest
- Avoid payday loans and loans with prepayment penalties
Common Loan Types and Typical Rates
| Loan Type | Typical APR Range | Common Terms |
|---|---|---|
| Personal loan (excellent credit) | 6–10% | 24–60 months |
| Personal loan (good credit) | 10–20% | 24–60 months |
| Auto loan (new car) | 5–9% | 36–72 months |
| Auto loan (used car) | 7–16% | 24–60 months |
| Home improvement loan | 7–15% | 24–84 months |
| Medical financing | 6–22% | 12–60 months |
The True Cost of Borrowing: Term Comparison
On a $15,000 personal loan at 12% APR, here's how your term choice changes the real cost:
| Term | Monthly Payment | Total Interest | Total Cost |
|---|---|---|---|
| 24 months | $706 | $1,946 | $16,946 |
| 36 months | $498 | $2,936 | $17,936 |
| 48 months | $395 | $3,960 | $18,960 |
| 60 months | $334 | $5,020 | $20,020 |
The 60-month option saves $372/month vs. 24 months — but costs $3,074 more in total interest. If you can afford the higher payment, shorter is almost always cheaper overall. Use this calculator to run both scenarios before deciding.
How to Compare Loan Offers the Right Way
Never compare loans by monthly payment alone — a lower payment usually just means a longer term and more interest paid. Always compare: (1) APR (the all-in annual cost including origination fees, not just the base interest rate), (2) total cost of borrowing (monthly payment × number of payments minus principal), and (3) prepayment terms (does the lender charge a penalty for paying early?). A loan with a slightly higher monthly payment and no prepayment penalty is often the smarter choice if you plan to pay it down faster.
How Much Can You Borrow?
Lenders size a loan from the payment, not the other way round. They cap your debt-to-income ratio (DTI) — all monthly debt payments ÷ gross monthly income — usually at 36% for the best terms and around 43% as a ceiling. The payment room left under that cap, run through the loan formula in reverse, is the most you can borrow: P = M × [1 − (1+r)−n] ÷ r.
Example: on $7,000 a month of gross income with $600 of existing debt payments, a 36% cap allows $2,520 of total debt, leaving $1,920 a month for a new loan. At 10% over 3 years that supports about $59,500; over 5 years, about $90,400 — but with far more interest. Paying off a $300 car payment first adds $300 of room, worth roughly $9,300 of extra borrowing at the same rate and term. Switch the calculator to "How much I can borrow" to run your own numbers.
Being approved for the maximum doesn't make it comfortable. At 43% DTI, over two-fifths of your gross pay goes to debt before taxes, food or savings. Keeping total debt payments under about 30% of gross income leaves real room for emergencies. DTI and credit score also measure different things: a 780 score won't rescue an application at 45% DTI, while a 680 score with a 22% DTI often gets approved.
Related Reading
Debt Avalanche vs. Debt Snowball: Which Pays Off Faster?
If you have multiple loans, the repayment strategy you choose affects both total interest paid and how quickly you become debt-free. Here's the data.
Loan Calculator — Frequently Asked Questions
Sources & method
This calculator implements the standard amortization formula — standard financial mathematics that no single body maintains as an official standard. The formula is shown on this page so you can verify it; "how much can I borrow" mode uses its inverse, P = M × [1 − (1+r)−n] ÷ r.
Debt-to-income definition: CFPB — What is a debt-to-income ratio?
Not financial or tax advice. This is an educational estimator. It does not know your full situation, and tax rules change. Akshaya Panda, who builds and verifies these tools, is an engineer — not a financial adviser, accountant, or tax professional. Before acting on a result that matters, check it with someone licensed to advise you.