Estate Tax Calculator
Estimate potential estate-tax exposure using gross estate value, deductions, lifetime taxable gifts, the remaining exemption, and an optional flat state estate-tax rate.
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🏦
Loan Interest Calculator
Calculate monthly loan payments, total interest, and total repayment for amortized or simple interest loans. Includes a full amortization schedule, yearly balance chart, and principal vs interest breakdown.
Amortized Loan Calculator
$
%
Monthly Payment
$299.71
per month × 36 payments
Total Repaid
$10,789.54
Total Interest
$789.54
Payments
36 monthly
Payment Breakdown
Principal 92.68%Interest 7.32%
Loan Summary
Loan Amount$10,000.00
Annual Rate5%
Monthly Rate0.4167%
ModeAmortized
Example: $10,000 Loan at 5% for 3 Years
Loan Amount
$10,000
Annual Rate
5%
Term
3 years
Monthly Payment
$299.71
Total Interest
$789.52
Total Repayment
$10,789.52
Step-by-step calculation
Monthly rate r = 5 / 12 / 100 = 0.004167Payments n = 3 × 12 = 36Formula M = 10000 × 0.004167 × (1.004167)^36 / ((1.004167)^36 − 1)Result M = $299.71 / monthTotal paid $299.71 × 36 = $10,789.52Total interest $10,789.52 − $10,000 = $789.52How Loan Interest Works
When you borrow money, the lender charges interest — a percentage fee on the outstanding balance. For most personal, auto, and mortgage loans, interest is calculated using amortization: each month, interest is charged on the remaining balance, then the rest of your payment goes toward principal.
This means early payments are mostly interest and late payments are mostly principal. Your monthly payment amount stays fixed, but the split between principal and interest shifts every month.
Why it matters: On a 30-year $200,000 mortgage at 6%, you pay $231,677 in interest alone — more than the original loan. Shortening the term or making extra payments dramatically reduces total interest.
| Payment | Principal | Interest | Balance |
|---|---|---|---|
| 1 | $258.04 | $41.67 | $9,741.96 |
| 2 | $259.12 | $40.59 | $9,482.84 |
| 3 | $260.20 | $39.51 | $9,222.64 |
| … | … | … | … |
| 36 | $298.46 | $1.25 | $0.00 |
Simple Interest vs Amortized Loans
📐 Simple Interest
Interest is calculated only on the original principal, regardless of remaining balance. Formula: I = P × r × t
Example: $10,000 at 5% for 3 years
I = 10,000 × 0.05 × 3 = $1,500
Total = $11,500📊 Amortized Loan
Interest is calculated on the remaining balance each month, which decreases with each payment. Standard for mortgages, car loans, personal loans.
Example: $10,000 at 5% for 3 years
Monthly = $299.71
Interest = $789.52 (less than simple)Key insight: Amortized loans charge less total interest than simple interest over the same term because you're paying down the principal each month — reducing the base on which interest is calculated.
Loan Repayment Tips
💸
Make Extra Principal Payments
Even small extra payments reduce the principal faster, shortening the loan and saving interest. On a $200,000 mortgage, $100 extra/month can save ~$30,000 in interest.
📅
Pay Biweekly Instead of Monthly
26 biweekly payments = 13 monthly payments per year (one extra). This can cut months off your loan and reduce total interest paid.
🏷️
Refinance When Rates Drop
If rates fall 1%+ below your current rate, refinancing may be worth it. Use this calculator to compare your current payment vs a new rate scenario.
📈
Improve Your Credit Score First
A 740+ credit score vs 650 can reduce your rate by 1-2%. On a $300,000 mortgage, that's $50,000+ difference in total interest paid.
⏱️
Choose the Shortest Affordable Term
A 15-year mortgage has a higher monthly payment than 30-year but saves enormous interest. Use this calculator to compare scenarios.
🚫
Avoid Interest-Only Periods
Interest-only loans defer principal paydown. You'll owe the same amount at the end of the IO period and still need to pay it all back.
Common Loan Types & Typical Rates
| Loan Type | Typical Rate | Typical Term | Type |
|---|---|---|---|
| Mortgage | 6–8% | 15–30 years | Amortized |
| Auto Loan | 5–10% | 3–7 years | Amortized |
| Personal Loan | 8–25% | 1–7 years | Amortized |
| Student Loan | 4–8% | 10–25 years | Amortized |
| Short-term Loan | 15–30% | 1–12 months | Simple/Amortized |
| Credit Card | 18–28% | Revolving | Compound |
Rates are approximate averages and vary by credit score, lender, and economic conditions.
Frequently Asked Questions
Explore This Tool in Context
Loan Interest Calculator is part of the Financial Calculators collection. If you want a broader view of similar workflows, open the Financial Calculators category page or browse all QuickTools categories.
Common next steps after this tool include Estate Tax Calculator, Social Security Calculator and Annuity Payout Calculator.
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