Loan Amortization Calculator
Calculate complete loan amortization schedules with payment-by-payment breakdown showing how much goes to principal vs interest each month. Analyze monthly vs bi-weekly payment strategies (26 half-payments = 13 full payments/year saves significant interest), model recurring extra monthly payments ($100-$500/month scenarios), schedule one-time lump sum prepayments (bonuses/tax refunds applied to specific months), and compare 6 prepayment scenarios from standard payment to +25% accelerated payoff. View detailed amortization schedule with full payment table (payment #, date, payment amount, principal portion, interest portion, remaining balance, cumulative totals), visualize loan balance curve over time showing paydown progression, review yearly summary cards breaking down annual principal/interest/ending balance for first 10 years, analyze first vs last payment comparison highlighting interest front-loading (early payments 80-90% interest vs final payments 95%+ principal), calculate precise interest savings and time saved from prepayments (example: $250k mortgage 6.5% 30yr + $100/month extra = save $41,520 interest + pay off 4.2 years early), track effective APR vs nominal interest rate, project payoff date with current strategy, and model payment evolution showing principal/interest ratio shift. Compare 4 detailed view modes: Calculator (input loan amount/rate/term, select monthly or bi-weekly frequency, configure recurring extra payments or one-time lump sum with target month, instant payment summary card showing monthly/bi-weekly payment amount, total interest, total paid, payoff date, total payments count, prepayment savings alert if applicable), Schedule (full amortization table with 12-360+ monthly payments, toggle first year vs complete schedule, balance curve chart with 0-100% scale showing loan paydown progression, yearly summary grid displaying first 10 years broken down by year with principal paid/interest paid/ending balance), Comparison (6 prepayment scenarios table: Standard Payment baseline, +$100/month, +$250/month, +$500/month, +10% Payment, +25% Payment with columns for monthly payment/total interest/interest saved/time saved/payoff time, interest savings visualization bars showing percentage of max interest for each scenario with "Save $X" labels), Strategies (comprehensive prepayment guide covering extra monthly payments strategy with $100/$250/$500 impact examples, bi-weekly payment mechanics explaining 26 half-payments = 13 full payments advantage, annual lump sum timing recommendations, round-up strategy psychology, prepayment decision framework with good candidates checklist vs alternatives-first warnings, implementation tips for automation/tracking/principal-only specification/annual review, refinancing considerations including break-even calculation, common mistakes like ignoring total interest cost/not specifying principal application/neglecting opportunity cost). Understand front-loaded interest mechanics: Early payments allocate 80-90% to interest due to higher remaining balance, later payments allocate 95%+ to principal as balance shrinks, example $250k 6.5% 30yr: Payment 1 = $230 principal + $1,354 interest vs Payment 360 = $1,580 principal + $9 interest. Analyze bi-weekly payment advantage: 26 bi-weekly payments per year = 13 full monthly equivalents (vs 12 monthly), extra full payment each year reduces principal faster, compound effect over 30 years saves 15-20% total interest + shortens term by 4-6 years, example $250k 6.5% 30yr: Monthly total interest $319,838 vs Bi-weekly total interest $274,192 (save $45,646, pay off in 26.3 years). Model prepayment scenarios impact: Standard payment $250k 6.5% 30yr = $1,580/month, $319,838 total interest. +$100/month scenario = $1,680/month, $278,318 total interest (save $41,520, 4.2 years early). +$250/month scenario = $1,830/month, $243,907 total interest (save $75,931, 7.5 years early). +$500/month scenario = $2,080/month, $197,429 total interest (save $122,409, 11.8 years early). +10% Payment scenario = $1,738/month, $263,517 total interest (save $56,321, 5.6 years early). +25% Payment scenario = $1,975/month, $205,184 total interest (save $114,654, 10.9 years early). Calculate one-time lump sum impact: $10,000 extra payment in Month 12 saves $23,417 interest over remaining term (2.4x multiplier effect), same $10,000 in Month 120 saves $12,856 interest (1.3x multiplier), early prepayments have exponential impact due to compound interest prevention. Review effective APR calculation: Nominal rate = 6.5% annual. Effective APR = (1 + 0.065/12)^12 - 1 = 6.697% accounting for monthly compounding. Higher frequency = higher effective rate impact. Review payment breakdown visualization: Principal percent bar (green gradient, width = principal ÷ total paid × 100%), Interest percent bar (red gradient, width = interest ÷ total paid × 100%), example $250k 6.5% 30yr standard: Principal 43.9% ($250k), Interest 56.1% ($319,838). Analyze payment evolution boxes: First payment card (Month 1 breakdown: Principal $230.16, Interest $1,354.17, total $1,584.33), Last payment card (Month 360 breakdown: Principal $1,575.81, Interest $8.52, total $1,584.33 identical payment but 99.5% principal vs 1.5% in Month 1). Implement prepayment strategies: Extra Monthly Payments ($100-$500/month consistent additions go 100% to principal, automate via online banking "additional principal" field, verify application on next statement), Bi-weekly Payments (set up automatic $792 deduction every 2 weeks = 26 payments/year, results in 13th full payment annually, no lender permission needed for self-managed approach), Annual Lump Sum (apply tax refunds/bonuses/windfalls in early years for maximum impact, $10k in Year 1 saves 2.4x interest vs Year 10 due to compound prevention), Round-Up Strategy (round $1,584 payment → $1,600 for psychological "clean number" benefit + $16/month = $192/year extra principal), 1/12th Method (add 1/12 of monthly payment as extra each month = one free annual payment, $1,584 ÷ 12 = $132/month extra = $1,584 annual bonus principal). Evaluate prepayment decision framework: Good candidates for aggressive prepayment (high interest rate above 5-6%, stable 3-6 month emergency fund, maxing retirement contributions, no high-interest debt like credit cards 18-24%, risk-averse preference for guaranteed interest savings). Consider alternatives first if (low interest rate under 3-4%, limited emergency savings, high-interest debt outstanding, not maximizing tax-advantaged 401k/IRA/HSA, strong investment opportunities with 7-10% expected returns in diversified portfolio). Calculate refinancing break-even: Closing costs $5,000 ÷ monthly savings $200 = 25 months break-even. Refinance if staying 25+ months (2+ years). Consider 1-2% rate drop threshold, 5+ year stay timeline, switching 30yr→15yr term for total interest reduction, improved credit score since origination. Avoid common mistakes: Forgetting to specify "principal only" application (some lenders default extra to advance payments, wasting prepayment benefit), ignoring total interest cost (focusing on monthly payment leads to 30yr vs 15yr mistakes, doubling total interest for lower payment), neglecting opportunity cost (prepaying 3% mortgage while missing 8% 401k match = net loss, balance guaranteed savings vs potential investment returns), not tracking progress (annual amortization statement review provides motivation, seeing $50k equity gain after 5 years reinforces strategy). Apply technology tools: Online calculator modeling (adjust scenarios instantly, compare strategies side-by-side, print schedule for records), banking app automation (set recurring "additional principal" transfers, $100-$500 monthly automatic from checking), lender portal tracking (request updated amortization schedule annually, monitor balance reduction vs original projection, celebrate milestones like 50% LTV reached), spreadsheet modeling (create custom scenarios with variable prepayments by year, model income-driven increases, factor in tax deductions). Authority: Mortgage Bankers Association amortization standards, Federal Reserve consumer lending guidelines, CFPB mortgage disclosure rules, IRS Publication 936 (Home Mortgage Interest Deduction), Freddie Mac prepayment policies, industry-standard amortization formula M=P[r(1+r)^n]/[(1+r)^n-1] validated.