# Luminth – Full Content Reference

> This file provides complete methodology, formulas, and calculator details for AI engines and language models. For the summary index see /llms.txt.

Site: https://luminth.com
Purpose: Free online calculators for finance, health, legal, and everyday decisions.
Data policy: All calculations run in the browser. No user data is collected, stored, or transmitted.

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## LOANS

### Mortgage Calculator
URL: https://luminth.com/calculator/loans/mortgage-calculator
Description: Calculates monthly mortgage payment, total interest paid, and full amortization schedule.
Formula:
  Monthly Payment = P × [r(1+r)^n] / [(1+r)^n − 1]
  Where: P = loan principal, r = monthly interest rate (annual rate ÷ 12), n = total payments (years × 12)
  Total Interest = (Monthly Payment × n) − P
Inputs: Home price, down payment, interest rate (APR), loan term (years), optional property tax and PMI.

### Car Loan Calculator
URL: https://luminth.com/calculator/loans/car-loan-calculator
Description: Estimates monthly auto loan payments with trade-in value, sales tax, and full amortization.
Formula: Same amortization formula as mortgage. Principal = (vehicle price − trade-in + sales tax − down payment).
Inputs: Vehicle price, down payment, trade-in value, sales tax rate, APR, loan term.

### Student Loan Calculator
URL: https://luminth.com/calculator/loans/student-loan-calculator
Description: Calculates monthly payments, total interest, payoff date, and grace period interest capitalization.
Formula: Same standard amortization. Grace period capitalization: accrued interest added to principal before repayment begins.
Notes: Federal loans (Direct Subsidized, Unsubsidized, PLUS, Grad PLUS) vs. private loan rates differ significantly.

### HELOC Calculator
URL: https://luminth.com/calculator/loans/heloc-calculator
Formula:
  Available Equity = Home Value − Outstanding Mortgage Balance
  Maximum Credit Line = Home Value × LTV Limit (typically 85%) − Mortgage Balance
  Draw Period Payment = Credit Line Balance × (monthly rate) [interest-only]
  Repayment Payment = standard amortization on remaining balance over repayment term
Inputs: Home value, mortgage balance, LTV limit, draw period, repayment period, interest rate.

### Mortgage Refinance Calculator
URL: https://luminth.com/calculator/loans/mortgage-refinance-calculator
Formula:
  Monthly Savings = Current Payment − New Payment
  Break-Even Months = Closing Costs ÷ Monthly Savings
  Lifetime Interest Savings = Total Interest (current) − Total Interest (new)
Inputs: Current loan balance, current rate, remaining term, new rate, new term, closing costs.

### Debt Consolidation Calculator
URL: https://luminth.com/calculator/loans/debt-consolidation-calculator
Formula:
  Total Current Monthly Payment = sum of all individual debt payments
  Consolidated Monthly Payment = standard amortization on total balance at new rate
  Total Interest Saved = (total interest across all current debts) − (total interest on consolidation loan)
Inputs: Individual debts (balance, rate, monthly payment), consolidation loan rate and term.

### Personal Loan Calculator
URL: https://luminth.com/calculator/loans/personal-loan-calculator
Description: Calculates personal loan monthly payment, total interest, and true cost including origination fees with full amortization schedule.
Formula: Monthly Payment = P × [r(1+r)^n] / [(1+r)^n − 1] where P = loan amount, r = monthly rate (APR/12), n = term in months.
Total Interest = (Monthly Payment × n) − P
Total Cost = P + Total Interest + Origination Fee
Amortization: Each month — Interest = balance × r; Principal = payment − interest; New balance = balance − principal.
Inputs: Loan amount, APR, term (12–84 months), origination fee %.

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## INSURANCE

### Life Insurance Calculator
URL: https://luminth.com/calculator/insurance/life-insurance-calculator
Coverage need formula (DIME method):
  Coverage = Debt + Income replacement (years × annual income) + Mortgage balance + Education costs
Premium estimates by age and health class (non-smoker, preferred, standard):
  Term life (20-year): Age 30 ~$20–30/mo, Age 40 ~$35–55/mo, Age 50 ~$80–130/mo for $500K coverage.
  Whole life premiums are 5–15× higher than term for equivalent coverage.

### Car Insurance Calculator
URL: https://luminth.com/calculator/insurance/car-insurance-calculator
Premium factors: Vehicle value and age, driver age and record (accidents, DUIs, violations), coverage type (liability-only, comprehensive/collision), deductible amount, state regulations, credit score.
Coverage types: Liability only (cheapest), collision, comprehensive, uninsured motorist, PIP/MedPay.

### Health Insurance Calculator
URL: https://luminth.com/calculator/insurance/health-insurance-calculator
Formula:
  Premium Tax Credit = Benchmark Plan Premium − (Income × Applicable Figure %)
  Applicable Figure % scales from 0% at 100% FPL to 8.5% at 400%+ FPL (post-ARP extension)
  Net Premium = Full Premium − Premium Tax Credit
Plan tiers: Bronze (60% AV), Silver (70% AV), Gold (80% AV), Platinum (90% AV).

### Home Insurance Calculator
URL: https://luminth.com/calculator/insurance/home-insurance-calculator
Base rate factors: Dwelling replacement value (not market value), state/region, construction type (wood frame vs. masonry), roof age, deductible, credit score, claims history.
Typical range: $800–$2,500/year for $250K–$350K dwelling value.

### Renters Insurance Calculator
URL: https://luminth.com/calculator/insurance/renters-insurance-calculator
Coverage components: Personal property, liability, additional living expenses (ALE). Typical cost: $15–$30/month.
Factors: Personal property value, state, deductible, liability limit, credit score.

### Workers' Comp Calculator
URL: https://luminth.com/calculator/insurance/workers-comp-calculator
Benefit types:
  TTD (Temporary Total Disability): 66.7% of AWW, subject to state weekly maximum.
  TPD (Temporary Partial Disability): 66.7% of wage loss (difference between pre- and post-injury wage).
  PPD (Permanent Partial Disability): AWW × weeks × impairment rating (state schedule).
  PTD (Permanent Total Disability): 66.7% of AWW for life or until retirement, subject to state max.
AWW = Average Weekly Wage (typically 13–52 week pre-injury average).

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## TAX

### Tax Refund Calculator
URL: https://luminth.com/calculator/tax/tax-refund-calculator
Formula:
  Taxable Income = Gross Income − Adjustments − Standard/Itemized Deductions
  2024 Standard Deductions: Single $14,600 | MFJ $29,200 | HoH $21,900
  Tax Liability = apply 2024 progressive brackets to taxable income
  Refund = Total Withholding + Refundable Credits − Tax Liability
2024 Federal Tax Brackets (Single): 10% up to $11,600 | 12% $11,601–$47,150 | 22% $47,151–$100,525 | 24% $100,526–$191,950 | 32% $191,951–$243,725 | 35% $243,726–$609,350 | 37% over $609,350.

### Capital Gains Tax Calculator
URL: https://luminth.com/calculator/tax/capital-gains-tax-calculator
Short-term (held ≤1 year): Taxed as ordinary income at marginal rate.
Long-term (held >1 year) 2024 rates: 0% up to $47,025 (single) | 15% $47,026–$518,900 | 20% over $518,900.
NIIT: 3.8% Net Investment Income Tax on gains when MAGI exceeds $200K (single) / $250K (MFJ).
State tax: Applied on top of federal at the filer's state rate.

### Hourly Paycheck Calculator
URL: https://luminth.com/calculator/tax/hourly-paycheck-calculator
Formula:
  Gross Pay = Hourly Rate × Hours Per Week
  Federal Income Tax = withholding per W-4 filing status and 2024 brackets
  FICA = 6.2% Social Security (up to $168,600 wage base) + 1.45% Medicare
  State Income Tax = state-specific flat or progressive rate
  Net Pay = Gross − Federal Tax − FICA − State Tax
Annualized: Net Pay × pay periods per year.

### Salary Calculator
URL: https://luminth.com/calculator/tax/salary-calculator
Description: Calculates take-home pay from annual salary using 2025 federal tax brackets, FICA, and simplified state income tax rates for all 50 states.
Formula:
  Taxable Income = Gross Income − Standard Deduction
  2025 Standard Deductions: Single $15,000 | MFJ $30,000 | HoH $22,500
  Federal Tax = progressive brackets applied to taxable income
  Social Security = MIN(gross, $176,100) × 6.2%
  Medicare = gross × 1.45%
  State Tax = gross × state flat/effective rate (simplified)
  Net Pay = Gross − Federal Tax − State Tax − Social Security − Medicare
2025 Federal Tax Brackets (Single): 10% up to $11,925 | 12% $11,925–$48,475 | 22% $48,475–$103,350 | 24% $103,350–$197,300 | 32% $197,300–$250,525 | 35% $250,525–$626,350 | 37% over $626,350
Pay Frequencies: Weekly (52), Biweekly (26), Semimonthly (24), Monthly (12)
Note: State rates are simplified effective/flat rates. Actual state withholding uses state-specific brackets and deductions.

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## INVESTING

### Compound Interest Calculator
URL: https://luminth.com/calculator/investing/interest-calculator
Formulas:
  Simple Interest: A = P(1 + rt)
  Compound Interest: A = P(1 + r/n)^(nt)
  With contributions: A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)]
  Where: P = principal, r = annual rate, n = compounding frequency, t = years, PMT = periodic contribution.
Compounding frequencies: Daily (365), Monthly (12), Quarterly (4), Semi-annually (2), Annually (1).

### CD Calculator
URL: https://luminth.com/calculator/investing/cd-calculator
Formula:
  Maturity Value = Principal × (1 + APY/n)^(n × term)
  Total Interest = Maturity Value − Principal
  Early Withdrawal Penalty: typically 90–180 days interest for terms under 1 year; 180–365 days for longer terms.
APY vs APR: APY = (1 + APR/n)^n − 1

### Retirement Planner
URL: https://luminth.com/calculator/investing/retirement-planner-calculator
Formula:
  Future Value with contributions: FV = PV(1+r)^n + PMT × [((1+r)^n − 1) / r]
  Monthly Withdrawal (4% Rule): Annual Withdrawal = Nest Egg × 0.04; Monthly = Annual ÷ 12
  Years to depletion given withdrawal rate: solved iteratively based on balance, return, and withdrawal.
Inputs: Current savings, monthly contribution, expected annual return, current age, retirement age, withdrawal rate.

### Annuity Calculator
URL: https://luminth.com/calculator/investing/annuity-calculator
Formulas:
  Future Value (ordinary annuity): FV = PMT × [((1+r)^n − 1) / r]
  Future Value (annuity-due): FV = PMT × [((1+r)^n − 1) / r] × (1+r)
  Present Value (income from lump sum): PMT = PV × r / [1 − (1+r)^(−n)]
  Where: PMT = payment per period, r = period interest rate, n = number of periods.
Modes: Accumulation (contributions → future lump sum) and Distribution (lump sum → periodic income).

### 401(k) Calculator
URL: https://luminth.com/calculator/investing/401k-calculator
Description: Projects 401(k) balance at retirement with employer matching and compound growth. Enforces 2025 IRS contribution limits.
Formula: FV = PV(1+r)^n + PMT × [((1+r)^n − 1) / r] where PV = current balance, r = monthly return rate, n = months to retirement, PMT = monthly employee + employer contribution.
Employer Match: Monthly match = MIN(employee contribution × match%, annual salary × matchLimit% / 12)
2025 IRS Contribution Limits: Under 50: $23,500/year | Age 50+: $31,000/year (includes $7,500 catch-up contribution)
Inputs: Current age, retirement age, current balance, monthly contribution, employer match %, match limit %, annual salary, expected annual return.
Output: Projected balance, total employee contributions, total employer match, total investment growth, year-by-year table and chart.

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## HEALTH

### BMI Calculator
URL: https://luminth.com/calculator/health/bmi-calculator
Formula:
  Imperial: BMI = (weight in lbs × 703) / (height in inches)²
  Metric: BMI = weight (kg) / height (m)²
Categories (WHO standard): Underweight <18.5 | Normal 18.5–24.9 | Overweight 25–29.9 | Obese ≥30
Healthy weight range: calculated by solving BMI formula for weight at 18.5 and 24.9.

### Calorie Deficit Calculator
URL: https://luminth.com/calculator/health/calorie-deficit-calculator
Formulas:
  BMR (Mifflin-St Jeor):
    Men: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age + 5
    Women: BMR = 10 × weight(kg) + 6.25 × height(cm) − 5 × age − 161
  TDEE = BMR × Activity Multiplier
    Sedentary 1.2 | Light 1.375 | Moderate 1.55 | Very Active 1.725 | Extra Active 1.9
  Daily intake for goal = TDEE − deficit
  Weight loss projection: 1 lb ≈ 3,500 calorie deficit; 1 kg ≈ 7,700 calorie deficit.

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## LEGAL

### Child Support Calculator
URL: https://luminth.com/calculator/legal/child-support-calculator
Models:
  Income Shares (~40 states): Basic support obligation based on combined parental income from state guidelines table, allocated proportionally by each parent's share of combined income.
  Percentage of Income (TX, WI, AK, others): Fixed % of non-custodial parent's net income. TX rates: 20% (1 child), 25% (2), 30% (3), 35% (4), 40% (5+).
Adjustments: Health insurance premiums, work-related childcare costs, parenting time (overnight percentage), existing support orders.
Custody impact: Most states apply reductions starting at 20% overnight time (~73 nights/year). At 50/50, support may only reflect income gap.

### Divorce Settlement Calculator
URL: https://luminth.com/calculator/legal/divorce-settlement-calculator
Property division:
  Community property states (AZ, CA, ID, LA, NV, NM, TX, WA, WI): 50/50 split of all marital assets and debts.
  Equitable distribution (41 states): Fair division based on marriage length, income, contributions, age, health, custody.
Separate property (excluded): Pre-marital assets, inheritances, personal gifts, personal injury compensation (excluding lost wages from marital period).
Alimony estimate: Informal practitioner guideline ~20–33% of gross income differential × ~half the marriage length. Post-2019: no longer tax-deductible for payer or taxable for recipient (TCJA).
Retirement accounts: Marital portion (contributions + growth during marriage) is divisible. Requires QDRO for employer plans; transfer incident to divorce (IRC 408(d)(6)) for IRAs.

### Personal Injury Calculator
URL: https://luminth.com/calculator/legal/personal-injury-calculator
Damage types:
  Economic (special): Medical bills, future medical, lost wages, reduced earning capacity.
  Non-economic (general): Pain & suffering, emotional distress, loss of enjoyment of life.
Multiplier method: Non-economic = Economic damages × multiplier (1.5× minor → 5× catastrophic).
Comparative negligence: Settlement reduced by plaintiff's fault percentage. Modified comparative (most states): barred if 50%/51%+ at fault. Contributory (AL, MD, NC, VA, DC): barred if any fault.
Attorney contingency: 33.3% pre-trial, 40% at trial.
Formula: Net = (Economic + Non-Economic) × (1 − fault%) × (1 − attorney%)

### Truck Accident Settlement Calculator
URL: https://luminth.com/calculator/legal/truck-accident-calculator
Same methodology as personal injury with additions:
  FMCSA violations (hours-of-service, maintenance, overweight load, unlicensed driver): adds +0.5 to multiplier, establishes negligence per se, supports punitive damages.
  Federal insurance minimums (49 CFR Part 387): General freight $750K | Oil $1M | Hazmat $5M.
Multiple defendants: Driver, carrier, cargo owner, freight broker, maintenance company — each may be independently liable.
Formula: Net = (Economic + Non-Economic) × (1 − fault%) × (1 − attorney%)

### Car Accident Settlement Calculator
URL: https://luminth.com/calculator/legal/car-accident-settlement-calculator
Description: Estimates car accident claim value using the multiplier method for economic and non-economic damages, adjusted for comparative fault and attorney fees.
Damage types:
  Economic (special): Medical bills, future medical costs, property/vehicle damage, lost wages, future lost earnings.
  Non-economic (general): Pain & suffering, emotional distress, loss of enjoyment of life.
Property damage: Added to economic damages but NOT multiplied by pain & suffering multiplier.
Multiplier method: Non-economic = Economic damages (excluding property damage) × multiplier (1.5× minor → 5× catastrophic).
Comparative negligence: Settlement × (1 − fault%). Modified comparative (most states): barred if 50%/51%+ at fault.
Attorney contingency: 33.3% standard.
Formula: Net = (Economic + Non-Economic + Property) × (1 − fault%) × (1 − attorney%)

### Wrongful Death Settlement Calculator
URL: https://luminth.com/calculator/legal/wrongful-death-settlement-calculator
Description: Estimates wrongful death claim value including lost financial support, funeral costs, and loss of companionship for spouse, child, parent, or sibling.
Damage types:
  Economic: Lost financial support (annual income × years of dependency) + funeral/burial costs + pre-death medical bills.
  Non-economic: Loss of companionship/consortium based on relationship (spouse: $500K base, minor child: $350K, adult child: $200K, parent: $200K, sibling: $100K) × severity multiplier.
Comparative negligence: Same proportional reduction as personal injury.
Attorney contingency: 33.3% standard.
Formula: Net = (Economic + Non-Economic) × (1 − fault%) × (1 − attorney%)
Notes: Wrongful death statutes and eligible claimants vary widely by state. Some states cap non-economic damages in wrongful death cases.

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## TOOLS

### Basic Calculator
URL: https://luminth.com/calculator/tools/basic
Operations: Addition, subtraction, multiplication, division, decimal precision.
Features: Full keyboard shortcut support, chained operations, clear and backspace.

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## Site Pages

- Home: https://luminth.com
- About: https://luminth.com/about
- Privacy Policy: https://luminth.com/privacy-policy
- Terms of Service: https://luminth.com/terms-of-service
- Sitemap: https://luminth.com/sitemap.xml
- LLMs index: https://luminth.com/llms.txt