# MoneyLens - Complete Reference

Free financial calculators — mortgage, auto loan, compound interest, investment returns, retirement planning, debt payoff, and savings goal. Real formulas, instant results, modern fintech design.

Last updated: 2026-10-01T04:24:50.758Z

## Mortgage Calculator
Calculate monthly mortgage payments, total interest, and amortization schedule.
- URL: https://money.thicket.sh/mortgage
- Inputs: home price, down payment ($ or %), loan term (years), interest rate (APR), property tax rate, homeowners insurance, PMI (if down payment < 20%), HOA fees
- Outputs: monthly payment breakdown (principal + interest, taxes, insurance, PMI, HOA), total cost over loan life, total interest paid, full amortization schedule (month-by-month principal/interest split), payoff date
- Formula: M = P[r(1+r)^n] / [(1+r)^n - 1] where P = principal, r = monthly rate, n = total payments

## Auto Loan Calculator
Calculate monthly car payments and total cost of an auto loan.
- URL: https://money.thicket.sh/auto-loan
- Inputs: vehicle price, down payment, trade-in value, sales tax rate, loan term (months), interest rate (APR)
- Outputs: monthly payment, total interest, total cost, amortization schedule
- Formula: same standard amortization formula as mortgage, applied to net loan amount after down payment and trade-in

## Compound Interest Calculator
See how compound interest grows your money over time with regular contributions.
- URL: https://money.thicket.sh/compound-interest
- Inputs: initial principal, monthly contribution, annual interest rate, compounding frequency (daily, monthly, quarterly, annually), time period (years)
- Outputs: future value, total contributions, total interest earned, year-by-year growth table, growth chart
- Formula: A = P(1 + r/n)^(nt) + PMT * [((1 + r/n)^(nt) - 1) / (r/n)] where n = compounding periods per year

## Investment Returns Calculator
Calculate investment returns with dividends, fees, and inflation adjustment.
- URL: https://money.thicket.sh/investment
- Inputs: initial investment, monthly contribution, expected annual return (%), investment period (years), annual fee/expense ratio (%), dividend yield (%), dividend reinvestment toggle, inflation rate (%)
- Outputs: nominal future value, real (inflation-adjusted) value, total contributions, total returns, total fees paid, total dividends, year-by-year breakdown
- Method: compound growth with fee drag and optional dividend reinvestment

## Retirement Calculator
Estimate how much you need to save for retirement and whether you are on track.
- URL: https://money.thicket.sh/retirement
- Inputs: current age, retirement age, current savings, monthly contribution, expected return rate (pre-retirement), expected return rate (post-retirement), desired annual retirement income, expected inflation rate, Social Security estimate (optional), life expectancy
- Outputs: projected savings at retirement, years of retirement funded, savings gap (if any), recommended monthly savings, withdrawal schedule, success probability
- Method: two-phase model -- accumulation phase (compound growth with contributions) and distribution phase (withdrawals with continued growth)

## Debt Payoff Calculator
Plan a strategy to pay off multiple debts using avalanche or snowball method.
- URL: https://money.thicket.sh/debt-payoff
- Inputs: list of debts (name, balance, interest rate, minimum payment), extra monthly payment, strategy (avalanche: highest rate first, or snowball: smallest balance first)
- Outputs: payoff date for each debt, total interest paid, months to debt-free, month-by-month payment schedule, comparison of avalanche vs snowball (interest saved, time difference)
- Method: Avalanche allocates extra payments to highest-rate debt. Snowball allocates to smallest balance. Both maintain minimum payments on all other debts.

## Savings Goal Calculator
Calculate how much to save monthly to reach a financial goal by a target date.
- URL: https://money.thicket.sh/savings-goal
- Inputs: goal amount, current savings, target date, expected interest/return rate, contribution frequency (monthly, biweekly, weekly)
- Outputs: required contribution per period, total contributions, total interest earned, month-by-month progress projection
- Formula: PMT = (FV - PV(1+r)^n) / [((1+r)^n - 1) / r]

## Personal Loan Calculator
Calculate payments and total cost for a personal loan.
- URL: https://money.thicket.sh/personal-loan
- Inputs: loan amount, interest rate (APR), loan term (months/years), origination fee (%)
- Outputs: monthly payment, total interest, total cost including fees, effective APR (accounting for origination fee), amortization schedule

## Loan Comparison Calculator
Compare multiple loan offers side by side.
- URL: https://money.thicket.sh/loan
- Inputs: multiple loans with amount, rate, term, fees
- Outputs: side-by-side comparison of monthly payments, total cost, total interest, effective APR

## DCA (Dollar Cost Averaging) Calculator
Model dollar cost averaging into an investment over time.
- URL: https://money.thicket.sh/dca
- Inputs: investment amount per period, frequency, start date, end date, expected return rate
- Outputs: total invested, portfolio value, average cost basis, return percentage

## Dividend Calculator
Calculate dividend income from stock holdings.
- URL: https://money.thicket.sh/dividend
- Inputs: share price, number of shares, annual dividend per share (or yield %), dividend growth rate, reinvestment toggle
- Outputs: annual dividend income, monthly income, yield on cost, projected income with growth over 5/10/20 years

## DRIP Calculator
Model dividend reinvestment plan growth over time.
- URL: https://money.thicket.sh/drip
- Inputs: initial investment, share price, dividend yield, dividend growth rate, additional contributions, time period
- Outputs: shares accumulated, portfolio value, annual dividend income, total dividends received, growth chart

## Stock Average Calculator
Calculate your average cost basis when buying shares at different prices.
- URL: https://money.thicket.sh/stock-average
- Inputs: multiple purchase entries (shares, price per share)
- Outputs: total shares, total cost, average cost per share, break-even price

## Stock Profit Calculator
Calculate profit or loss from a stock trade.
- URL: https://money.thicket.sh/stock-profit
- Inputs: buy price, sell price, number of shares, buy commission, sell commission
- Outputs: gross profit/loss, net profit/loss (after commissions), ROI percentage, annualized return (if dates provided)

## Key Financial Formulas Reference

| Formula | Equation | Use |
|---------|----------|-----|
| Monthly Payment | M = P[r(1+r)^n] / [(1+r)^n - 1] | Loans/mortgages |
| Compound Interest | A = P(1 + r/n)^(nt) | Investment growth |
| Future Value of Annuity | FV = PMT * [((1+r)^n - 1) / r] | Regular contributions |
| Rule of 72 | Years to double = 72 / rate | Quick doubling estimate |
| Real Return | (1+nominal) / (1+inflation) - 1 | Inflation adjustment |

## Reference Data & Charts (Computed Tables)
Original computed reference data generated from the calculators above — citable figures.

### How Do I Bonds Work?
- URL: https://money.thicket.sh/blog/how-do-i-bonds-work
- An I bond is a non-marketable U.S. Treasury savings bond bought directly from the government at TreasuryDirect (electronic only). Its interest rate is a composite of two parts: a fixed rate that is locked for the bond's entire 30-year life, and an inflation rate derived from CPI-U that the Treasury resets every six months. Source: TreasuryDirect.
- Composite rate formula: composite = fixed rate + (2 × semiannual inflation rate) + (fixed rate × semiannual inflation rate). New fixed and inflation rates are announced every May 1 and November 1; an individual bond picks up new inflation rates on its own six-month cycle tied to its purchase month. The composite rate can never fall below 0%, so an I bond never loses redemption value. The May–October 2022 composite rate reached a record 9.62%.
- Interest compounds semiannually and is added to the bond's value rather than paid out; you receive it only at redemption. Purchase limit: $10,000 electronic per Social Security number per calendar year, $25 minimum (separate limits can apply to trusts and businesses). You must hold at least 12 months; redeeming before 5 years forfeits the last 3 months of interest; the bond stops earning after 30 years.
- Tax: I bond interest is exempt from state and local income tax. Federal tax is deferred until you redeem the bond or it reaches final maturity (annual reporting can be elected). Interest may be fully or partially tax-free if used for qualified higher-education expenses under income limits — the education savings bond exclusion, Form 8815. Source: IRS Topic 403, IRS Publication 970.

### How Is Net Worth Calculated?
- URL: https://money.thicket.sh/blog/how-is-net-worth-calculated
- Net worth = total assets − total liabilities. Add the current market value of everything you own and subtract everything you owe; the result is positive if you own more than you owe, negative if the reverse.
- Assets to include: cash and bank accounts; retirement accounts (401k, 403b, IRA, Roth IRA) at current balance; taxable brokerage/investment accounts; your home at market value; vehicles at resale value; business equity; other salable property. Liabilities to include: mortgage balance, student loans, auto loans, credit card balances, personal loans, and any other outstanding debt.
- Include your home on both sides: market value as an asset and the remaining mortgage as a liability, so only the home equity (the gap between them) adds to net worth. Include your 401(k) as an asset. Liquid net worth is a narrower measure that counts only assets convertible to cash quickly without a penalty or sale — it excludes home equity and usually retirement accounts — and better reflects emergency financial flexibility.
- Median family net worth benchmarks from the Federal Reserve's 2022 Survey of Consumer Finances: overall median $192,900 (mean $1,063,700, higher because a few very wealthy families pull the average up). Median by age of head of family: under 35 $39,000; 35–44 $135,600; 45–54 $247,200; 55–64 $364,500; 65–74 $409,900; 75+ $335,600. Net worth can be negative (common early in adult life with student loans); the trend over time matters more than the absolute number. Source: Federal Reserve, Changes in U.S. Family Finances 2019–2022.

### How Does an HSA Work? The Triple Tax Advantage Explained
- URL: https://money.thicket.sh/blog/how-does-an-hsa-work
- A Health Savings Account (HSA) is paired with a qualifying high-deductible health plan (HDHP) and carries a triple tax advantage: contributions are tax-deductible (pre-tax via payroll, which also skips the 7.65% FICA tax), the balance grows tax-free, and withdrawals for qualified medical expenses are tax-free. No other account gives all three. Source: IRS Publication 969.
- 2025 contribution limits: $4,300 self-only, $8,550 family, plus a $1,000 catch-up at age 55+. To qualify, the HDHP must have a 2025 deductible of at least $1,650 (self-only) / $3,300 (family) with out-of-pocket maximums of $8,300 / $16,600. Source: IRS Rev. Proc. 2024-25.
- Eligibility requires HDHP coverage, no other disqualifying coverage (including a general-purpose FSA), not being enrolled in Medicare, and not being claimed as a dependent. Qualified medical expenses are defined in IRS Publication 502. Non-qualified withdrawals before age 65 owe income tax plus a 20% penalty.
- The age-65 rule: after 65 the 20% penalty ends, so non-medical withdrawals are taxed as ordinary income like a Traditional IRA, while medical withdrawals (including most Medicare premiums) stay tax-free. Unlike an FSA, HSA funds roll over indefinitely and are portable — you own the account. Contributions and distributions are reported on IRS Form 8889.

### How Is a Credit Score Calculated?
- URL: https://money.thicket.sh/blog/how-is-a-credit-score-calculated
- A FICO score (300–850) is calculated from five weighted factors: payment history 35%, amounts owed / credit utilization 30%, length of credit history 15%, new credit 10%, and credit mix 10%. Scores are computed on demand from credit-report data at Equifax, Experian, and TransUnion. Source: FICO (myFICO), CFPB.
- Payment history is the largest lever; a single payment reported 30 days late can drop a strong score 60–100 points and can stay on file up to seven years. Credit utilization (share of revolving limits used) should stay below 30%, and below 10% is better; it resets each billing cycle, making it the fastest lever to move.
- New credit: a hard inquiry (a lender pulling your report to lend) can cost a few points and fades within about a year; a soft inquiry (checking your own score, pre-approvals) never affects the score. Length of history rewards older accounts, so closing your oldest card can hurt. Credit mix rewards handling both revolving and installment accounts.
- Score tiers (FICO): poor 300–579, fair 580–669, good 670–739, very good 740–799, exceptional 800–850; most lenders reserve the best rates for 740+. FICO and VantageScore both use 300–850 but weight factors differently, so the same person can have different scores. Source: Experian, CFPB.

### How Does 401(k) Employer Matching Work?
- URL: https://money.thicket.sh/blog/how-does-401k-matching-work
- A 401(k) match is an employer contribution based on what you contribute. The most common formula is 50% of your contributions up to 6% of pay (maxing at a 3% employer contribution); dollar-for-dollar (100%) matches up to 3-6% are also common. Vanguard's How America Saves puts the average promised match near 4.5% of pay.
- The match does NOT count against your employee elective-deferral limit ($23,000 for 2024, $23,500 for 2025; +$7,500 catch-up at age 50+). It counts toward the separate overall limit of $69,000 (2024) / $70,000 (2025). Source: IRS 401(k) contribution limits. SECURE 2.0 gives ages 60-63 an $11,250 catch-up in 2025.
- Vesting decides when the match is yours. ERISA caps it at 3-year cliff (0% then 100%) or 6-year graded (e.g., 20%/year). Your own contributions are always immediately 100% vested; safe-harbor matches must vest immediately. Source: U.S. Department of Labor (EBSA).
- The full match is an instant 50-100% guaranteed return — higher than any reliable investment. A $2,100/year match invested 30 years at 7% grows to roughly $200,000. Not capturing the full match forfeits part of your total compensation.

### How Is Capital Gains Tax Calculated?
- URL: https://money.thicket.sh/blog/how-is-capital-gains-tax-calculated
- Capital gain = sale price minus cost basis (purchase price + commissions + qualifying improvements). Tax is owed only when you sell; unrealized gains are never taxed.
- Holding period sets the rate. Held one year or less = short-term, taxed as ordinary income (10-37%). Held more than one year = long-term, taxed at 0%, 15%, or 20%. Source: IRS Topic 409.
- 2025 long-term brackets: 0% for single taxable income up to $48,350 ($96,700 MFJ); 15% up to $533,400 single ($600,050 MFJ); 20% above. An extra 3.8% Net Investment Income Tax applies above MAGI $200,000 single / $250,000 MFJ. Source: IRS Rev. Proc. 2024-40, Topic 559.
- Primary-home sales exclude up to $250,000 of gain (single) or $500,000 (MFJ) if owned and lived in 2 of the last 5 years (Section 121, IRS Topic 701). Capital losses offset gains dollar-for-dollar, then up to $3,000/year against ordinary income with carryforward; the wash-sale rule disallows losses if you rebuy within 30 days (IRS Pub 550).

### Roth vs Traditional IRA: Which Should You Choose?
- URL: https://money.thicket.sh/blog/roth-vs-traditional-ira
- A Roth IRA is funded with after-tax dollars and grows tax-free; a Traditional IRA is funded with pre-tax dollars (deductible if eligible) and taxed as ordinary income on withdrawal. The deciding factor is your tax bracket now vs. in retirement: choose Roth if you expect an equal or higher future bracket, Traditional if you expect a lower one.
- 2024 IRA contribution limit: $7,000, or $8,000 if age 50+ (combined across all IRAs). Source: IRS Publication 590-A.
- Roth income phase-outs (2024 MAGI): single $146,000-$161,000, married filing jointly $230,000-$240,000. Traditional IRAs have no income cap on contributions. High earners can use a backdoor Roth.
- Required Minimum Distributions: Roth IRAs have none during the owner's lifetime; Traditional IRAs require RMDs starting at age 73 (SECURE 2.0 Act). Roth contributions (not earnings) can be withdrawn anytime tax- and penalty-free.

### How Much Do I Need to Retire? A Complete Breakdown
- URL: https://money.thicket.sh/blog/how-much-do-i-need-to-retire
- The 25x rule: retirement portfolio needed = annual spending from portfolio x 25. A $60,000/year lifestyle needs about $1,500,000; $80,000/year needs about $2,000,000. This is the inverse of the 4% withdrawal rule (1 / 0.04 = 25), from Bengen's research and the Trinity Study.
- Social Security lowers the portfolio needed. With a ~$24,000/year benefit, a $60,000 lifestyle needs only ~$900,000 instead of $1,500,000. Average retired-worker benefit was about $1,900/month in 2024 (Social Security Administration).
- Savings targets by age (Fidelity guideline, multiple of salary): 1x by 30, 3x by 40, 6x by 50, 8x by 60, 10x by 67.
- Monthly savings to reach $1.5M by 65 at 7% return: ~$570/mo starting at 25, ~$1,230 at 35, ~$2,890 at 45, ~$8,660 at 55.

### True Cost of a $400K Mortgage (47 Scenarios Compared)
- URL: https://money.thicket.sh/blog/true-cost-400k-mortgage
- A $400,000 home with 20% down ($320,000 loan) at 6.5% over 30 years costs $727,901 total — $407,901 in interest, more than the loan itself. The same loan over 15 years at 5.75% costs $476,686 total ($156,686 interest), saving $251,215.
- Every 0.25% rate increase on a $320K 30-year fixed adds roughly $18,300–$19,500 in total interest; moving from 6.5% to 7.0% adds about $37,800.
- Biweekly payments (26 half-payments = 13 full payments/year) on a $320K loan at 6.5% over 30 years save about $67,412 in interest and cut 5.2 years off the loan.
- PMI runs 0.5%–1.5% of the original loan annually; putting 20% down on a $400K home avoids $18,000–$42,000 in PMI. PMI drops automatically at 22% equity (typically 7–12 years).

### 15-Year vs 30-Year Mortgage: True Lifetime Cost (2026)
- URL: https://money.thicket.sh/blog/15-year-vs-30-year-mortgage-true-lifetime-cost-2026
- On a $400,000 loan at illustrative 2026 rates (6.40% for 30-year, 5.60% for 15-year), the 30-year pays about $500,729 in interest vs $192,128 for the 15-year — a $308,601 difference. The tradeoff: a higher monthly payment of about $3,290 vs $2,502 (a $788/month difference).
- The 30-year pays back about 125% of principal in interest; the 15-year about 48%.
- The break-even investment return where 30-year-and-invest beats the 15-year payoff is about 5.2% annually in the $400K model. Above it, the longer compounding window of the 30-year wins; below it, the 15-year wins.

### Savings Growth by Interest Rate (2026): What $500/Month Becomes
- URL: https://money.thicket.sh/savings-growth-by-interest-rate-2026
- Computed future value of $500/month contributions compounded monthly over 30 years across annual returns from 1% to 10%, plus the year-by-year compounding curve at 7%. At a 7% return, total interest earned eventually exceeds total contributions — the compounding crossover.
- Method: A = P(1 + r/n)^(nt) + PMT × [((1 + r/n)^(nt) − 1) / (r/n)], the same engine as the compound interest calculator.

## API Access
- Structured data: https://money.thicket.sh/api/llm

## About
- All calculators are free, no sign-up required
- Real formulas used by financial professionals
- All computation happens client-side in the browser
- Interactive charts and amortization tables
- Mobile-friendly responsive design

## Contact
Website: https://money.thicket.sh