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Find your monthly payment, total interest and total cost for any loan amount, APR and term.
Enter the loan amount, annual percentage rate (APR) and term in years. The calculator applies the standard amortization formula and shows your fixed monthly payment, total interest and total amount repaid.
Formula: Monthly payment = P × r(1+r)^n ÷ ((1+r)^n − 1), where r = APR ÷ 12 and n = years × 12. Example: $20,000 at 9% APR for 4 years → $497.70/month, $3,889.64 total interest.
Quick answer: A $20,000 personal loan at 9% APR repaid over 4 years costs $497.70 per month — 48 payments totaling $23,889.64, of which $3,889.64 is interest. The monthly payment comes from the amortization formula M = P × r(1+r)n ÷ ((1+r)n − 1), where r is the monthly interest rate and n is the number of payments. Enter your own loan amount, rate, and term in the calculator above for exact figures, then read the full guide below for step-by-step instructions, how personal loans work, the formula with fully worked examples, two detailed borrowing scenarios, the five costliest mistakes, and related tools.
Using the Personal Loan Calculator takes under a minute. You enter three numbers — how much you want to borrow, the annual interest rate, and the repayment term — and it instantly shows your monthly payment, total interest, and total repayment. Here is how to use it well.
Step 1 — Enter the loan amount (principal). Type the amount you need to borrow, not the amount you wish you needed. Example: for a $22,000 car where you have a $2,000 down payment, enter $20,000. Borrowing exactly what you need matters because every extra $1,000 borrowed at 9% over 4 years adds about $24.89 per month and $194.48 in total interest.
Step 2 — Enter the annual interest rate (APR). Use the APR from your loan offer, not the advertised “starting at” rate. In 2024–2025, typical personal loan APRs range from about 7% for excellent credit (750+) to 18–25% for fair credit (630–689). Example: entering 9% versus 14% on a $20,000, 4-year loan changes the payment from $497.70 to $542.18 — a $44.48 monthly difference and $2,134.90 more interest over the life of the loan.
Step 3 — Choose the loan term in years. Common personal loan terms are 2, 3, 4, 5, or 7 years. Shorter terms mean higher monthly payments but much less total interest. Example: that same $20,000 at 9% costs $497.70/month over 4 years ($3,889.64 interest) but $640.66/month over 3 years ($3,063.76 interest) — one year shorter saves $825.88 in interest.
Step 4 — Read the three headline numbers. The calculator shows your monthly payment ($497.70 in our example), total interest ($3,889.64), and total repayment ($23,889.64). These three numbers are everything: the payment must fit your monthly budget, and the total interest tells you the true price of borrowing.
Step 5 — Test scenarios before you sign. Run at least three combinations: your best-case rate, your likely rate, and a longer term. If the payment at your likely rate exceeds 15–20% of your monthly take-home pay, the loan is probably too big or the term too short. Example: on $4,500 monthly take-home pay, a $497.70 payment is 11.1% — comfortable; a $862.76 payment (the 4-year $35,000 loan in Example 2 below) would be 19.2% — tight.
Step 6 — Recalculate when offers arrive. Lenders quote exact APRs after a credit check. Plug each real offer into the calculator — a 1.5% rate difference on $20,000 over 4 years is worth $704.16 in total interest, easily outweighing a “low fee” marketing claim.
A personal loan is a lump sum of money you borrow from a bank, credit union, or online lender and repay in fixed monthly installments over a set period, typically 2–7 years. Most personal loans are unsecured, meaning no collateral (like a house or car) backs the loan — the lender relies on your credit score and income to judge risk. Because there is no collateral to repossess, unsecured rates run higher than mortgage or auto loan rates: expect roughly 7–12% with excellent credit, 13–20% with good-to-fair credit, and 25%+ with poor credit.
The principal is the amount you borrow. The annual percentage rate (APR) is the yearly cost of borrowing expressed as a percentage, and — crucially — it includes most lender fees, unlike the bare interest rate. A loan with a 9% interest rate plus a 5% origination fee has an APR noticeably above 9%; always compare loans by APR, not by interest rate. The loan term is the repayment period; the amortization schedule is the month-by-month table showing how each payment splits between interest and principal.
Amortization has a quirk borrowers should understand: early payments are mostly interest. On that $20,000, 9%, 4-year loan, the first $497.70 payment contains $150.00 of interest and only $347.70 of principal; the final payment contains $3.71 of interest and $493.99 of principal. This is why refinancing or making extra payments early in the loan saves far more than extra payments near the end — extra principal paid in month 6 avoids 42 months of interest on that amount, while extra principal in month 42 avoids only 6.
Lenders also apply two tests before approving you. The debt-to-income ratio (DTI) — your total monthly debt payments divided by gross monthly income — usually must stay under 36–43% including the new loan payment. And your credit score bands determine your rate: 720+ typically unlocks the best advertised rates, 690–719 adds roughly 1–2%, 630–689 adds 4–8%, and below 630 often means denial or rates above 25%. A $20,000 loan at 9% versus 19% over 4 years is the difference between $3,889.64 and $8,847.52 in total interest — a $4,957.88 penalty for weaker credit, which is why checking your score before applying pays.
The calculator uses the standard amortizing loan payment formula:
M = P × r(1+r)n ÷ ((1+r)n − 1)
Where M is the monthly payment, P is the principal (loan amount), r is the monthly interest rate (annual APR ÷ 12), and n is the total number of monthly payments (years × 12). Total repayment = M × n, and total interest = (M × n) − P.
Worked Example 1. Borrow $20,000 at 9% APR for 4 years. Step 1: monthly rate r = 0.09 ÷ 12 = 0.0075. Step 2: number of payments n = 4 × 12 = 48. Step 3: (1.0075)48 ≈ 1.4314. Step 4: M = 20,000 × 0.0075 × 1.4314 ÷ (1.4314 − 1) = 214.71 ÷ 0.4314 ≈ $497.70 per month. Total repayment = 497.70 × 48 = $23,889.64; total interest = 23,889.64 − 20,000 = $3,889.64. This matches the calculator above exactly.
Worked Example 2. Borrow $10,000 at 7% APR for 3 years. Step 1: r = 0.07 ÷ 12 ≈ 0.005833. Step 2: n = 36. Step 3: (1.005833)36 ≈ 1.2329. Step 4: M = 10,000 × 0.005833 × 1.2329 ÷ 0.2329 ≈ $308.76 per month. Total repayment = 308.76 × 36 = $11,115.36; total interest = $1,115.36. Notice how halving the principal and shortening the term collapses the interest cost — the interest here is just 11.2% of the amount borrowed, versus 19.4% in Example 1.
Quick sanity check you can do mentally: divide the total interest by the principal. If the answer exceeds about 25% on a 4–5 year loan, your rate is high or your term is long — shop for a better offer or shorten the term.
Meet Ahmed, 41, who carries $15,000 across three credit cards at an average 22.9% APR, paying about $450/month in minimums — of which roughly $286 is interest, so his balances barely move. He takes a $15,000 personal loan at 11% APR for 5 years and uses it to clear all three cards. The math: r = 0.11 ÷ 12 ≈ 0.009167, n = 60, (1.009167)60 ≈ 1.7289, so M = 15,000 × 0.009167 × 1.7289 ÷ 0.7289 ≈ $326.14 per month. Total repayment = 326.14 × 60 = $19,568.40; total interest = $4,568.40.
Compare the two paths. Staying on the cards at $450/month and 22.9%: he would pay for about 52 months and hand over roughly $8,400 in interest. With the consolidation loan at $326.14/month: he pays $123.86 less each month and saves about $3,831.60 in total interest, with a fixed end date 60 months out. The critical discipline: Ahmed must not run the credit cards back up — consolidation only works if the cards stay near zero, otherwise he ends up with the loan plus new card balances. His rule: cards stay in a drawer, and the $123.86 monthly savings goes straight to an emergency fund until it reaches $5,000.
Now meet Fatima and Hassan, who need $35,000 for a home renovation and qualify for 8.5% APR. They debate a 6-year versus a 4-year term. Here are both, computed with the formula.
Option A — 6 years (72 payments): r = 0.085 ÷ 12 ≈ 0.007083, (1.007083)72 ≈ 1.6623, M = 35,000 × 0.007083 × 1.6623 ÷ 0.6623 ≈ $622.24/month. Total repayment = 622.24 × 72 = $44,801.28; total interest = $9,801.28.
Option B — 4 years (48 payments): (1.007083)48 ≈ 1.4032, M = 35,000 × 0.007083 × 1.4032 ÷ 0.4032 ≈ $862.76/month. Total repayment = 862.76 × 48 = $41,412.48; total interest = $6,412.48.
The trade-off is stark: Option B costs $240.52 more per month but saves $3,388.80 in total interest and frees them from debt two years sooner. Their decision rule: with $6,800 combined monthly take-home pay, the $862.76 payment is 12.7% of income — within the safe zone — so they take the 4-year term and keep the $3,388.80. If the payment had exceeded 20% of take-home pay ($1,360), the 6-year term would have been the prudent choice despite the extra interest. This is exactly the comparison the calculator above is built for — run both terms before you choose.
Mistake 1 — Shopping by monthly payment alone. A lender stretches a $20,000 loan at 12% from 4 years to 7 years: the payment drops from $527.68 to $352.06 — but total interest jumps from $5,328.64 to $9,573.04, a $4,244.40 penalty for the “affordable” payment. Fix: compare total interest and APR first, payment second.
Mistake 2 — Ignoring the APR in favor of the interest rate. Loan A: 9% rate, no fees. Loan B: 8.5% rate with a 5% origination fee ($1,000 on $20,000, often deducted from the disbursement so you receive $19,000 but repay $20,000). Loan B’s APR is roughly 10.3% — worse than Loan A despite the lower advertised rate. Fix: line up the APRs; they are legally required to include most fees.
Mistake 3 — Borrowing more than needed “while you’re at it.” Adding $3,000 of unneeded borrowing to a $20,000, 9%, 4-year loan raises the payment by $74.66/month and adds $583.44 in interest — for money that will likely be spent, not invested. Fix: borrow the exact project cost minus your cash contribution, then add a 5% contingency buffer, not 25%.
Mistake 4 — Not checking prepayment penalties. Some loans charge 1–2% of the remaining balance if you repay early. On a $15,000 balance, a 2% penalty is $300 — wiping out much of the benefit of an early payoff. Fix: ask “is there any prepayment penalty?” before signing, and prefer loans without one so you can overpay when cash allows.
Mistake 5 — Automatically taking the longest term. Lenders default to quoting 5–7 year terms because longer terms maximize their interest income. On $25,000 at 10%, choosing 7 years over 4 years cuts the payment from $635.65 to $412.17 but adds $4,921.32 in total interest ($9,721.32 vs $4,800). Fix: choose the shortest term whose payment stays under 15–20% of your monthly take-home pay.
A personal loan decision rarely stands alone. Use the Loan Calculator to compare other loan structures side by side, and the Amortization Calculator to see the full month-by-month schedule — exactly how much of each payment goes to interest versus principal, and how extra payments shorten the loan. Together with the Personal Loan Calculator above, the three tools cover every number that matters before you borrow.
Entity: Personal Loan Calculator — computes monthly payment, total interest, and total repayment for a fixed-rate amortizing personal loan. Core formula: M = P × r(1+r)n ÷ ((1+r)n − 1); r = APR ÷ 12; n = years × 12; total = M × n; interest = total − P. Reference example: $20,000 at 9% APR for 4 years → $497.70/month; $23,889.64 total; $3,889.64 interest; 48 payments. Second example: $10,000 at 7% for 3 years → $308.76/month; $11,115.36 total; $1,115.36 interest. Typical terms: 2–7 years; typical APRs 7–25% by credit tier. Key concepts: principal, APR (includes fees), amortization (early payments are interest-heavy), unsecured lending, origination fees, prepayment penalties, debt-to-income ratio (target <36–43%). Decision rule: shortest term with payment ≤15–20% of monthly take-home pay; compare offers by APR and total interest, not payment alone.
Sources: Consumer Financial Protection Bureau — personal loan guidance; Federal Reserve — household debt and credit data; Truth in Lending Act (Regulation Z) APR disclosure standards.
About $497.70 per month — 48 payments totaling $23,889.64, of which $3,889.64 is interest. Try the personal loan calculator above.
With the amortization formula: payment = principal × monthly rate × (1 + rate)^n ÷ ((1 + rate)^n − 1). Higher rates or longer terms change the payment.
Yes, but you pay more interest overall. Stretching the example above to 6 years drops the payment to about $357 but raises total interest to roughly $5,700.
APR includes lender fees folded into the yearly cost, so it is the truer comparison number when shopping for personal loans.
Usually yes, but check for prepayment penalties first. Extra principal payments shorten the term and cut total interest — run the numbers in the calculator above.