If this is what you are holding
Skip the category grid. Match the paper in your hand.
Twins that should not share a sentence
Same word on two buttons. They will not agree.
Payment
Amortization wants a loan amount, an annual rate, a term in years, a start date, and an extra monthly payment. Every row splits interest from principal. Extra money moves the payoff date.
Auto loan starts from the vehicle. Price, down payment, trade-in, rebates, sales tax, title fees, then a rate and a term in months. Fees sit in their own boxes. Fold them into the loan only when the quote does.
APR starts from a nominal rate plus fees, a term in months, and a payment frequency. A 6% offer with a $400 fee is a worse deal than the sticker. Amortization never sees that fee unless you bury it in the principal yourself. Use APR when the offers disagree on charges. Use amortization when you already trust the amount financed and you want the schedule.
Return
ROI looks backward. Starting cash, ending value, extra costs, years, income received, a tax rate. The menu has simple ROI, annualized ROI, and after-tax ROI. Annualized is the line that lets a two-year hold sit next to a six-year hold.
Stock return is one lot. Shares, buy price, today's price, cash dividends. On that page, a lot up 34% over two years compounds to about 15.8% a year. Divide 34 by 2 and you get 17%. The shortcut scores year two against the original pile.
Three buys? Blend the price yourself. The form keeps one lot. Short sales are rejected.
Investment return looks forward. Initial cash, a rate you hope for, years, extra contributions yearly or monthly. With nothing extra, $10,000 at 8% for 10 years prints $21,589. A yearly contribution is added after that year's growth, not on 1 January. Past results are not a promise. The page says so.
Later money
Future value grows a sum at a rate, for a term, at a compounding frequency you pick. Annual, semiannual, quarterly, monthly, daily. An extra payment is optional, and it compounds on the same frequency, end of each period. The figure ignores inflation.
Those two growth pages agree on one case only. No extra deposit, compounding once a year. Switch future value to monthly, or switch investment return to a monthly contribution, and the balances split. Investment return's monthly path divides the annual rate by 12. Future value divides by the frequency you chose.
Present value pulls one future sum back to today. Discount rate, periods, compounding. Two offers that pay on different dates are two runs. A string of unequal amounts does not fit the box.
Annuity is the series of equal payments. Ordinary or due. The menu solves for the payment, the present value, or the future value. A level pension estimate belongs here. A single check in five years belongs on present value.
The business
Margin and markup are the same sale wearing two names.
A $15 cost and a $25 price. Profit margin prints a 40% margin and a 66.7% markup. Someone says "we run at 40" without naming which, and the price is already wrong. The P&L mode separates gross, operating, and net. Card fees left in overhead make gross look fatter than the deposit.
Break-even wants fixed costs, variable cost per unit, and price. $10,000 of fixed cost and a $10 contribution is 1,000 units. It does not know a margin goal. Price the unit on the margin page. Then ask how many you must sell.
Pay
Payroll estimates one check. Annual, monthly, per-check, or hourly. Hourly annualizes as rate times hours per week times 52, then the schedule splits it. Weekly, biweekly, semimonthly, monthly, or once a year. Federal, state, Social Security, and Medicare are percents you type.
Not a W-2. Not a filing.
Tax on the income tab uses federal brackets. Multiply the whole wage by the top bracket and you overstate the bill. The page's own case: $86,000 times 22% prints $18,920 and overstates federal tax by $8,830. Payroll mode on the tax page is FICA, not a full stub. A stub belongs on the payroll page. A flat state rate here is one number you type, not a state bracket book.
The car, twice
Lease wants price, residual, months, a money factor, down payment, sales tax, an acquisition fee, and a disposition fee. A loan rate sits beside them for a comparison. A money factor of 0.0025 is 6% if you multiply by 2,400. The page states that conversion. Miles over the allowance, and the wear charge, stay off the form.
If the residual is the interesting number, the auto loan page is the wrong one. If you are buying, the lease page is the wrong one.
Cash from a share
Dividend projects income from a share count, a dividend per share, a frequency, and a growth rate, over the years you set. It does not mark the stock to market.
Stock return wants dividends already received, in cash, on the lot you still hold. Yield, and a payout that grows, are the other page.
One truck, four answers
The depreciation page already walks a $48,000 truck, $8,000 salvage, five years. Straight line charges $8,000 a year. Double declining charges $19,200 in year one, because 2 divided by 5 is 40%, applied to the full $48,000. Salvage is a floor, not the base. Book value after that year is $28,800.
A credit file that names straight line will not accept the other number. The gap in year one is $11,200.
Book value is not the classifieds.
The loan is a different split. Amortization follows the payment. The depreciation method does not change what the bank is owed. Buy the truck on the auto loan page when tax, title, and a down payment are part of the quote. Term there is months. Term on amortization is years.
Bought in October?
The depreciation ledger still takes a full year. Partial years are not applied. Half-year convention is a tax rule. It is not on this page. The tax page will not turn the schedule into a deduction, and it will not look up a recovery period.
The currency menu on depreciation changes the symbol only. A dollar cost next to a euro salvage is a nonsense subtraction. Convert first. Then read what the currency page multiplies by. That page is not a market.
Quote on the desk? Type the dealer price, the rate, and the months into the auto loan calculator before you initial the sheet. If the payments disagree by more than a cent, a fee is sitting outside the loan.
Baked numbers, wishful rates
Future value will compound as often as you tell it. Monthly is not annual. Inflation is still absent. A bigger balance in ten years is not a bigger life. I would not show a client the raw future value and call it purchasing power.
The inflation page is the place for the basket, and only the official one. History mode uses BLS CPI-U, US city average, all items, 1913 through 2026. 2025 is the last full year. 2026 is an estimate. It takes the 2025 average and raises it by the 3.4% yearly change BLS reported for August 2026. Projection mode uses a rate you pick, with chips for a long-run average. Your rent, your tuition, your diesel. None of those have to match the index. The page says personal inflation differs from the average. Believe that line.
FIRE asks for the return, the inflation rate, the tax rate, the fees, and the multiplier, on top of savings, contributions, and spending. You supply every one of them. A 25-times spending figure is the 4% rule, typed in by you. It is not a finding the page made.
Social Security is not on the form.
Payroll withholding has the same soft spot. Type 22 because a bracket chart said 22, and you repeat the mistake the tax page already flags. The percent boxes do not look up a table.
Currency is the blunt one. The converter holds a fixed table of fifteen currencies inside the script. USD to EUR is 0.925 there. The surrounding copy talks about live rates. The script does not fetch them. I would not put a figure from the table on an invoice.
Do not wire money from this page.
Bond price is the other baked formula, and this one is honest about its inputs. Face, coupon, market yield, years. The page sample is a $1,000 face, a 5% coupon, a 4% yield, 10 years, and it prints $1,081. Yield below the coupon, price above par. Know the coupon alone, and you still do not know the price.
The whole shelf, one refusal each
Twenty pages. If a name is missing, it is not in this category. A house payment is under calculators, linked at the bottom.
After the printout looks too clean
- The currency page talks about live rates. Is the figure a quote?
- No. The script multiplies by a fixed table. USD to EUR is 0.925 in the table. Fifteen currencies, no fetch, no market timestamp. A bank spread would sit on a rate already stale. Do not wire money from it. Do not put it on an invoice.
- ROI, stock return, and investment return. Which return?
- ROI looks backward at cash you already know, including a tax rate. Stock return is one lot, buy against today, plus dividends you already received in cash. Investment return looks forward from a rate you type. Three pages, three questions. A two-year hold and a six-year hold belong on ROI with annualized selected, or the short hold looks stronger than the long one.
- A car quote is in front of me. Amortization or auto loan?
- Auto loan. Term is months. Tax, title, trade-in, and rebates have their own boxes. Amortization wants a principal, a term in years, and an extra monthly payment. Type 60 months on one page and 5 years on the other, or the payments will not match. A fee stuffed into the amount financed belongs in the APR page first.
- Will payroll file, or keep the salary I typed?
- Neither. You type gross pay, a schedule, and withholding percents. The check is an estimate. Federal, state, Social Security, and Medicare are rates you supplied, not a W-4 lookup. The math stays in the browser. A full stub with federal withholding belongs here. FICA alone belongs on the tax page, payroll mode.
- Future value went up. Did prices?
- The future value page ignores inflation. $10,000 at 8% for 10 years, compounded once a year, with no extra payment, is $21,589. The result is a bigger count of dollars, not a bigger basket. Take the ending figure to the inflation page if you need older dollars, or a forward guess at a rate you choose. History mode uses BLS CPI-U. Your rent is not the city average.
- $86,000 times my top bracket. Is that the federal bill?
- No. The tax page flags this one. $86,000 times 22% prints $18,920 and overstates the federal bill by $8,830. Brackets fill from the bottom. A flat state percent on that page is a single rate you type, not a state table. Depreciation from the other page will not become a deduction here.
Wrong room
A mortgage, and a plain loan payment with no car worksheet, live with the calculators. Mean, deviation, and regression are statistics. This shelf is the schedule, the car, the lease, the tax estimate, the margin, and the growth math. The math stops where the assumption starts.