Calculators that show their work.

Project the growth of savings and investments with inflation-adjusted (real) returns, fees, taxes, contribution step-ups, and a full year-by-year breakdown.

Find how much to set aside each month to hit a target by a deadline — or how long your current pace will take.

CAGR, total return, and the true money-weighted return (IRR) when you add contributions — plus the inflation-adjusted real return.

Project dividend income with reinvestment (DRIP), rising payouts, and yield-on-cost — and see how much DRIP adds over taking cash.

The exact trades to hit your target allocation — plus a no-sell, contributions-only mode that rebalances without triggering taxable sales.

Compare two expense ratios side by side and see the dollars — and the share of your gains — that fees quietly consume over time.

Maturity value and interest from a certificate of deposit — plus what an early-withdrawal penalty would actually cost you.

Grow a savings balance at a real APY — and see what tax on interest and inflation leave you with in today’s money.

RSU value at vest, sell-to-cover shares, and the 22% withholding gap that leaves higher earners owing more at tax time.

The true investment yield on a T-bill (not just the quoted discount yield), the APY, and its state-tax-free advantage.

Your ESPP discount and lookback turned into a real return — the immediate gain and the eye-opening annualized rate.

Turn a nominal rate into its true APY, compare APY across compounding frequencies, and see the real dollars earned.

Simple and compound interest side by side — the total interest each way, the final balance, and exactly how many dollars compounding adds on top.

What a lump sum and regular contributions grow to at any rate and compounding frequency — with the split between what you put in and the interest you earn.

What a future lump sum or stream of payments is worth in today’s money once discounted — and how much value is lost to time at a given rate.

The compound annual growth rate that links a starting and ending value over time — the single rate that makes investments of different lengths comparable.

Future value with continuous compounding (P·e^(rt)), the effective annual rate it produces, and how much it beats compounding just once a year.

The present value interest factor of an annuity — the multiplier that turns a stream of equal payments into a single present value, behind loan and bond pricing. Educational, not investment advice.

The recurring deposit needed to accumulate a target amount by a future date — an annuity run in reverse, with the interest the compounding does for you. Educational, not investment advice.

The present value of a stream of payments that rises at a constant rate each period — for inflation-linked income, escalating leases, or growing dividends. Educational, not investment advice.

Your total return on an investment — capital gain plus income as a percentage of what you paid — split into the price return and the income return.

Convert between nominal and real interest rates using the exact Fisher equation — (1 + nominal) = (1 + real)(1 + inflation) — not just the nominal-minus-inflation shortcut.

Return on investment from what you put in and got back — plus the annualized (compound) ROI, the only fair way to compare investments held for different lengths of time.

Monthly payment, full amortization schedule, the true lifetime cost of interest, and how extra payments shorten your loan.

Payment, total interest, and payoff timeline for any fixed-rate loan, with an amortization breakdown.

The monthly payment on any fixed-rate loan — plus total interest, the true APR once fees are counted, and a full amortization schedule with extra-payment savings.

Monthly payment, total cost, and effective APR on a business loan — with origination fees folded in and a full amortization schedule so you can compare offers honestly.

See how long a fixed payment takes to clear your balance — and how the shrinking minimum-payment trap costs you years and thousands in interest.

Compare the snowball and avalanche strategies across all your debts — payoff order, total interest, and which one frees you sooner.

Whether refinancing pays off: the new payment, the break-even point on closing costs, and the term-reset interest trap.

How much house you can afford using real front-end and back-end DTI ratios — and which one is actually limiting your budget.

A true opportunity-cost comparison: invested down payment, appreciation, full ownership costs, and the year buying pulls ahead.

The real out-the-door cost — sales tax with the trade-in credit, fees, and the negative-equity timeline showing when you stop being underwater.

Whether a 0% balance transfer pays off once the fee and the go-to APR are counted — plus the payment to clear it before the promo ends.

Your front-end and back-end DTI, the lender qualification band you fall in, and how much debt headroom you have before 36% and 43%.

Pay off an existing loan faster — compare extra, biweekly, and lump-sum strategies, or solve the payment to be debt-free by a target date.

Your available credit from home equity, and the payment shock when the interest-only draw period flips to amortizing repayment.

Standard repayment vs an income-driven plan based on your discretionary income — the lower payment and the long-term tradeoff.

A full month-by-month amortization schedule with the principal-vs-interest crossover, extra payments, and CSV export.

How much car you can responsibly afford using the 20/4/10 rule — counting insurance and fuel, not just the loan payment.

Payment and true cost of an SBA business loan, including the SBA guarantee fee and the long terms SBA financing allows.

Whether buying discount points pays off — the upfront cost, the lower payment, and the break-even month you must pass to win.

Your monthly PMI and the full cancellation timeline — the 80% point you can request it gone and the 78% automatic cutoff.

FHA payment with upfront and annual MIP — including the catch that with under 10% down, MIP never cancels for the life of the loan.

An itemized estimate of buyer closing costs — and the total cash to close you actually need to bring to the table.

Whether buying out your car lease is smart — the all-in buyout cost vs the car’s market value, and the equity it captures.

Turns a small-sounding fee into its true APR (often 400%+), models the rollover trap, and compares the cost to safer credit.

Qualify a rental on its cash flow: the DSCR from rent and expenses, whether it clears the lender target, and the max loan it supports.

The true cost of a credit-card cash advance — the fee, the higher APR, and the no-grace-period interest that starts on day one.

Convert a car lease money factor to its equivalent APR (and back) — multiply by 2400 — so you can compare lease financing against a loan on equal terms.

Model contributions, employer match, and withdrawals to see whether your nest egg lasts through retirement.

Your financial-independence number, years to reach it, your Coast FIRE figure, and savings rate — all in today’s money.

After-tax retirement outcomes for Roth vs Traditional — including investing the up-front tax saving and your break-even tax rate.

Project your 401(k) with the real IRS contribution limits and catch-up — and see the employer match you’re leaving on the table.

Project tax-free Roth growth within the IRS contribution limits, and see exactly how much the tax-free growth beats a taxable account.

Required minimum distributions using the real IRS Uniform Lifetime Table, projected across every year with the estimated tax on each.

Estimate your benefit with the real PIA bend-point formula, and see how claiming from 62 to 70 changes your monthly check.

Short- vs long-term tax compared, the dollar benefit of crossing the one-year mark, and your after-tax annualized return.

Estimate your 2025 federal income tax with a bracket-by-bracket breakdown, FICA, and your true marginal vs effective rate.

Lump sum vs annuity, after federal and state tax — compared on a present-value basis so you see which option really wins.

See why a large gift almost never triggers tax — the per-recipient annual exclusion and the lifetime exemption, explained.

Tax across multiple crypto disposals — short vs long-term, loss netting, and the reminder that crypto-to-crypto trades are taxable.

Powerball cash value vs the 30-year graduated annuity, after federal and state tax, compared on a present-value basis.

Mega Millions lump sum vs annuity after tax, with the 30 graduated payments and a present-value comparison.

Convert any pay rate — hourly, daily, weekly, biweekly, semimonthly, monthly, or annual — into the equivalent at every other frequency, accounting for your real hours and weeks worked.

Turn an hourly, weekly, or monthly rate into your true annual income, with your real hours and weeks worked factored in — not just a flat ×2,080.

Convert an annual salary into the equivalent hourly wage, adjusting for the hours and weeks you actually work so the rate reflects your real schedule.

See what your hourly wage adds up to over a full year — and at every pay period in between — based on the hours and weeks you work.

Work out your gross monthly income from any pay rate — useful for budgets and rent or loan applications that ask for a monthly figure.

Find your wage at any pay rate and frequency — hourly, daily, weekly, biweekly, monthly, or yearly — with your real hours and weeks worked built in.

Calculate your pay every two weeks (26 paychecks a year) from any rate — and see exactly how it differs from a twice-a-month semimonthly check.

Work out your twice-a-month paycheck (24 a year) from any pay rate — and see why it’s larger, but less frequent, than biweekly pay.

Turn any pay rate into your weekly gross pay — and see the monthly and annual equivalents alongside it.

The percentage change between two consecutive periods — the momentum metric behind analytics and KPI dashboards — with the absolute change alongside.

Find your gross margin from cost and price, or price a product to hit a target margin — with the markup, profit, and the margin-vs-markup distinction made clear.

Work out the markup on a product, or set a price from a target markup — and see why a markup is always a bigger number than the margin it produces.

Calculate gross profit margin from revenue and cost, see the dollar profit per unit, and price to a target margin — the number that protects your bottom line.

Convert between margin and markup and see both at once for any cost and price — so you never price off the wrong one and quietly lose profit.

Return on ad spend from revenue and ad cost — plus the full funnel (CPM, CPC, CTR, conversion rate, CPA, ROI) so you see what is really driving the number.

Cost per thousand impressions from spend and impressions — with CPC, CTR, conversion rate, CPA, ROAS, and ROI for the same campaign in one view.

Click-through rate from clicks and impressions — alongside the rest of the funnel so you can tell whether a high CTR is actually converting.

Your conversion rate from conversions and clicks — with cost per conversion, ROAS, and ROI so you know what each conversion costs and earns.

Price European calls and puts with the Black-Scholes-Merton model — live Greeks, an implied-volatility solver, the profit-and-loss payoff at expiry, and the full working shown step by step. Educational, not trading advice.

Price European and American calls and puts on a Cox-Ross-Rubinstein lattice — watch it converge to Black-Scholes, and see the early-exercise premium that closed-form models miss. Educational, not trading advice.

Price options by simulating thousands of random price paths, watch the estimate converge to Black-Scholes, and see how the standard error shrinks with the square root of the path count. Educational, not trading advice.

Find the return an investment should earn for its market risk with the Capital Asset Pricing Model — risk-free rate plus beta times the equity risk premium, broken down step by step.

Value a dividend stock with the Gordon Growth model — the present value of all future dividends from D₁ ÷ (r − g) — and see why the result is so sensitive to the spread between return and growth.

Estimate intrinsic value by discounting projected free cash flows plus a terminal value back to today — with a per-year breakdown and how much of the value rests on the terminal assumption.

Compute the weighted average cost of capital — the blend of the cost of equity and the after-tax cost of debt by their weights — the discount rate that powers a DCF.

Price a bond from its yield, or solve the yield to maturity from a market price — with the premium/discount, current yield, and the cash flows behind the number. Educational, not trading advice.

Measure risk-adjusted return: the excess return over the risk-free rate per unit of volatility, with the calculation shown step by step. Educational, not investment advice.

Price a forward or futures contract by cost-of-carry — spot grown by financing and storage, less income and convenience yield — and see whether the market is in contango or backwardation. Educational, not trading advice.

Visualize the profit-and-loss at expiry for spreads, straddles, strangles, covered calls, and iron condors — with Black-Scholes-priced legs, break-evens, and max profit and loss. Educational, not trading advice.

Chart delta, gamma, vega, theta, and rho across the underlying price to see how an option’s risk sensitivities shift as the spot moves toward and past the strike. Educational, not trading advice.

Compute Macaulay and modified duration plus convexity, and see how the two together estimate a bond’s price change for a yield move far better than duration alone. Educational, not investment advice.

Net present value of a cash-flow series at your discount rate — with the per-period discounting, the profitability index, and a clear accept/reject signal. Educational, not investment advice.

The internal rate of return — the discount rate at which a project’s NPV is zero — solved numerically, with the NPV profile drawn so you can see exactly where it crosses zero. Educational, not investment advice.

Present value of a level or growing perpetuity (C ÷ r, or C ÷ (r − g)) — the engine behind dividend-growth valuation and DCF terminal values. Educational, not investment advice.

Risk-adjusted return using downside deviation only — the refinement of the Sharpe ratio that stops penalising upside volatility, shown side by side with Sharpe on your data. Educational, not investment advice.

The probability-weighted expected return across scenarios, plus the variance and standard deviation that measure its risk — the foundation of portfolio theory and CAPM. Educational, not investment advice.

Market cap from share price and shares outstanding, with the mega/large/mid/small/micro-cap tier — the equity value the market places on the whole company. Educational, not investment advice.

Enterprise value — the true takeover cost of a business: market cap plus debt, preferred, and minority interest, less cash — built up step by step from the balance sheet. Educational, not investment advice.

The price-to-earnings ratio from share price and EPS (or net income and shares), plus the earnings yield it implies — the most-quoted valuation multiple. Educational, not investment advice.

The P/E-to-growth ratio that puts a high multiple in context — a 30× P/E is cheap if earnings grow 30% a year — with a plain-English read on whether growth justifies the price. Educational, not investment advice.

The enterprise-multiple that values the whole business against its cash earnings — capital-structure-neutral, so debt-heavy and debt-free firms compare on equal footing. Educational, not investment advice.

The P/B ratio comparing market price to accounting book value, with the premium or discount to book — most telling for asset-heavy businesses like banks. Educational, not investment advice.

Return on equity — net income as a percentage of shareholders’ equity — the headline measure of the return a company earns on its owners’ capital. Educational, not investment advice.

Return on assets — profit as a percentage of everything the company owns — showing how efficiently its whole asset base is turned into earnings, unflattered by leverage. Educational, not investment advice.

Return on invested capital — after-tax operating profit (NOPAT) over the capital put to work — the truest test of operating quality, and the number to compare against the cost of capital. Educational, not investment advice.

Return on capital employed — operating profit over long-term capital (assets minus current liabilities) — a pre-tax measure favoured for capital-intensive companies. Educational, not investment advice.

Return on sales — operating income as a percentage of revenue — the operating margin that captures pricing power and cost control before financing and tax. Educational, not investment advice.

Decompose return on equity into profit margin, asset turnover, and financial leverage — the DuPont identity that reveals what is really driving a company’s ROE. Educational, not investment advice.

A bond’s current yield — annual coupon income as a percentage of its market price — and how it sits between the coupon rate and the yield to maturity at a premium or discount. Educational, not investment advice.

The cash coupon a bond pays each period — face value times coupon rate, split by frequency — plus the annual income and the total coupons over the bond’s life. Educational, not investment advice.

Recover a bond’s coupon rate from its periodic payment and face value — the fixed rate set at issue, which (unlike the yield) never changes with the market price. Educational, not investment advice.

Annualize the yield on a discount instrument like a T-bill — the bond-equivalent yield (gain on price, 365-day year) alongside the quoted bank-discount yield, so it compares with coupon bonds. Educational, not investment advice.

The pre-tax yield a taxable bond must offer to match a tax-free municipal bond in your tax bracket — and a side-by-side check of which one actually wins. Educational, not investment advice.

Earnings per share — profit for common shareholders divided by shares outstanding, with preferred dividends removed first. The per-share building block behind the P/E and PEG ratios. Educational, not investment advice.

Total and annualized (compound) growth in earnings per share between two periods — the engine behind the PEG ratio and a core test of whether a high multiple is justified. Educational, not investment advice.

Benjamin Graham’s ceiling for a defensive buy — √(22.5 × EPS × book value per share) — plus the margin of safety versus the current price. Educational, not investment advice.

Per-share intrinsic value via Graham’s revised formula — EPS × (8.5 + 2g) discounted by the corporate bond yield — with the margin of safety against today’s price. Educational, not investment advice.

Net asset value per share — total assets minus liabilities, divided by shares — the figure mutual funds price at and the benchmark for premiums and discounts. Educational, not investment advice.

How efficiently a company turns its assets into sales — revenue divided by total assets, the efficiency lever in the DuPont breakdown of return on equity. Educational, not investment advice.

How many times a year a company sells and replaces its inventory — cost of goods sold over average inventory — plus the days-inventory-outstanding holding period. Educational, not investment advice.

How quickly a company collects what it is owed — credit sales over average receivables — with the days-sales-outstanding average collection period. Educational, not investment advice.

Core operating profitability before financing, tax, and depreciation — EBITDA as a percentage of revenue — for comparing companies with different capital structures. Educational, not investment advice.

The share of earnings a company keeps to reinvest rather than pay out — the plowback ratio, equal to one minus the dividend payout, and the input to sustainable growth. Educational, not investment advice.

The fastest a company can grow funding itself — return on equity times the retention ratio — without raising new equity or increasing leverage. Educational, not investment advice.

How many days, on average, a company takes to pay its suppliers — accounts payable over COGS — the third leg of the cash conversion cycle. Educational, not investment advice.

How many days cash is tied up between paying suppliers and collecting from customers — days inventory plus days sales minus days payable. A negative cycle means suppliers fund the business. Educational, not investment advice.

Roll retained earnings forward — beginning balance plus net income minus dividends — the running total of profits a company has kept rather than paid out. Educational, not investment advice.

The interest rate the yield curve implies for a future period, derived by no-arbitrage from two spot rates. Educational, not investment advice.

How much of a stock’s price is growth expectation — the present value of growth opportunities, price minus the value of its earnings as a no-growth perpetuity. Educational, not investment advice.

Purchasing power in both directions, the cumulative erosion of a fixed sum, and the income you’d need to keep pace.

Map your real expenses into the 50/30/20 needs/wants/savings buckets, see which one you overspend, and find your savings rate.

How many months you’re covered today, a recommended 3–6 month target band, and how long it takes to get there at your pace.

Turn a mix of weekly, monthly, and yearly subscriptions into one true annual cost — and see what investing it instead would be worth.

Tip on the pre-tax subtotal (not the tax), split the bill any number of ways, round up, and compare common tip percentages.

Categorized assets and liabilities, your liquid vs illiquid split and debt-to-asset ratio, and a multi-year net-worth projection.

Compare two cities and find the salary you’d need to keep your standard of living — with a category-by-category breakdown.

Per-card and overall utilization against the 30%/10% guidance — plus the exact paydown to reach a target ratio.

How much coverage you need via the DIME method (debt, income, mortgage, education) — not a crude multiple of your income.

Split a wedding budget across categories using typical industry percentages, with the per-guest cost that drives the total.

Sale price and amount saved — including stacked discounts (which multiply, not add) and the real out-the-door price with tax.

Work out the sale price and dollars saved for any percent off — plus stacked "extra % off" coupons (which multiply, not add) and the final price with tax.

Turn a percentage discount into the price you actually pay and the amount you save — with support for a second stacked discount and sales tax.

Gross pay with time-and-a-half and double-time tiers, the overtime premium, and a weekly-to-annual breakdown.

Prorated rent for a partial month by all three methods (actual days, 30-day, annualized) so you can match your lease.