📊 Interest Rate Calculator
Interest Rate Calculator — Find Your True APR
Reverse-engineer the real interest rate on any loan, convert APR to APY, or compare two loan offers side by side. See exactly what you're paying.
🔍 Find Rate from Payment
🔄 APR ↔ APY Converter
⚖️ Side-by-Side Compare
📊 Principal vs Interest
Interest Rate Calculator
Find Rate · Convert APR/APY · Compare Loans
🔍 Find Rate
🔄 APR ↔ APY
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Loan Details
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Loan B
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APR
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Total Interest
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Principal
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Cost Breakdown
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📊 How Does This Rate Compare?
Typical 2026 loan rates by credit score — your calculated rate is highlighted
| Credit Score | Typical Rate | Monthly Pmt (same loan) | Total Interest |
|---|
💡 Interest Rate Tips
📈Improve your credit score before applying — even 20 points can lower your rate by 1–2%
🏦Compare at least 3 lenders — credit unions often beat bank rates by 1–2%
⏱️Shorter loan terms usually carry lower rates — and save significantly on total interest
💰A larger down payment reduces the loan amount, which can also lower your rate
📋Always compare APR, not just the interest rate — APR includes fees for a true cost comparison
🔄Consider refinancing if rates drop 1%+ below your current rate — savings can be substantial
What Is APR and Why Does It Matter?
APR (Annual Percentage Rate) is the true cost of borrowing expressed as a yearly rate. Unlike the stated "interest rate," APR includes fees and other costs associated with the loan, making it the most accurate way to compare loan offers.
For example, a loan advertised at "5.5% interest" might actually have a 6.2% APR once origination fees and closing costs are included. The monthly payment difference might seem small, but over a 30-year mortgage that extra 0.7% adds up to tens of thousands of dollars.
APR vs APY — Key Differences
| Feature | APR | APY |
|---|---|---|
| Full Name | Annual Percentage Rate | Annual Percentage Yield |
| Compounding | Does NOT include compounding | INCLUDES compounding effect |
| Value | Always ≤ APY | Always ≥ APR |
| Used For | Loans (mortgage, auto, personal) | Savings accounts, CDs, investments |
| Formula | Stated rate | (1 + APR/n)^n − 1 |
| Example (6% APR monthly) | 6.000% | 6.168% |
How Credit Score Affects Your Interest Rate
| Credit Score | Rating | Typical Auto Rate | Typical Mortgage Rate | Personal Loan Rate |
|---|---|---|---|---|
| 720+ | Excellent | 5–6.5% | 6–6.8% | 8–12% |
| 680–719 | Good | 6.5–9% | 6.8–7.5% | 12–16% |
| 640–679 | Fair | 9–13% | 7.5–8.5% | 16–22% |
| 580–639 | Poor | 13–18% | 8.5–10% | 22–30% |
| Below 580 | Very Poor | 18%+ | Hard to qualify | 30%+ |
Frequently Asked Questions
Enter the loan amount, term, and monthly payment into the "Find Rate" tab. The calculator uses Newton-Raphson numerical solving to reverse-engineer the exact APR. This is useful when a lender quotes only a monthly payment without clearly stating the interest rate — which happens frequently in auto dealerships and personal loan marketing.
APR (Annual Percentage Rate) is the stated interest rate without compounding. APY (Annual Percentage Yield) includes the compounding effect and is always slightly higher than APR. Banks advertise APY for savings accounts to show the true annual return, and APR for loans. Formula: APY = (1 + APR/n)^n − 1, where n = compounding periods per year.
In 2026: mortgage rates are roughly 6–7% for excellent credit. Auto loans are 5–7% for excellent credit, 9–13% for fair credit. Personal loans range from 8–12% for good credit. Credit cards average 18–24%. Any rate significantly above these benchmarks suggests either lower creditworthiness or an unfavorable loan product — use our comparison tool to assess your offer.
The impact depends on loan size and term. On a $30,000 auto loan at 60 months: 1% rate difference ≈ $14/month = $840 total. On a $300,000 mortgage at 30 years: 1% rate difference ≈ $183/month = $66,000 total interest difference. For long-term, large loans, even 0.5% matters enormously — always shop multiple lenders.
A high monthly payment with a "low" rate usually means a short loan term. Shorter terms require faster repayment regardless of rate. Use our calculator to verify: enter your loan amount, term, and monthly payment — the revealed APR tells you if the rate is genuinely low or if the payment is high due to a short term combined with a moderate rate.