Help & documentation

Use the calculators for a quick answer, then open the comparison, chart, and export tools when you want to test the answer more carefully.

Calculator guides

Each guide explains what the calculator works out, what its main values mean, how to read the result, and which assumptions deserve another scenario.

Investment growthProject a balance or solve for the starting money, contribution, return, or time a goal needs. 401(k) & IRARead future balances, compare Roth with traditional treatment, and understand required distributions. Roth conversionCompare conversion schedules, tax-bracket room, Medicare surcharges, RMDs, and after-tax wealth against a no-conversion baseline. Total compensationProject salary, bonus, RSU vesting, refresh grants, ESPP benefits, and future compensation cliffs. PaycheckEstimate W-2 take-home pay after withholding, payroll taxes, benefits, and deductions, then compare jobs or locations. Retirement & FIRETest whether money lasts and compare traditional, FIRE, Coast FIRE, and Barista FIRE milestones. 529 & collegeTranslate future education costs into child-specific targets and a required family saving pace. Loan & mortgageCompare housing payments, PMI, upfront cash, estimated APR, payoff dates and extra-payment plans. Rent vs. buyCompare both housing choices with the same cash and interpret net worth and lasting break-even. Rental propertyEstimate pre-tax cash flow, operating return, equity, sale proceeds, and how another exit year changes the result. PortfolioTrack holdings, allocation, unrealized gain or loss, daily moves, and separate portfolios. Mortgage vs. investFollow the same extra cash into principal or the market and compare the result at one horizon.

Getting started

  1. Choose a calculator from the calculator bar.
  2. Where a page offers several questions, choose what should be calculated. The other fields stay as inputs.
  3. Change an input. The answer, charts, and tables update automatically.
  4. Open the sections below the form to inspect how the result changes over time.
Investment growth calculator with numbered markers around the calculator bar, page controls, calculation mode, answer, and scenario bar.
  1. 1
    Calculator bar moves between the twelve calculators.
  2. 2
    Page controls export, show tips, reset inputs, and change theme.
  3. 3
    Calculation mode chooses the unknown the page should solve.
  4. 4
    Live answer summarizes the current scenario.
  5. 5
    Scenario bar starts with one plan and can add comparisons.

Inputs and answers

Type for precision; slide for speed

The number box is the saved value. Its slider is a convenient view of a common range. You can type a value beyond that comfortable slider range; the slider may stay at its end without changing the number you entered.

Expand advanced options only when they matter

Advanced options hold assumptions such as inflation, contribution timing, taxes, or compounding. The section heading summarizes important non-default choices so they remain visible when the section is closed.

Validation is all-or-nothing

If an input is missing or outside the page's supported bounds, fix the marked field before relying on the result. The page hides an invalid result instead of leaving an older answer on screen.

Compare scenarios and pin what matters

Select + to add another scenario, then change one or more assumptions. A calculator can keep up to five scenarios. Select a tab to edit it, use the coloured dot for its chart colour, or drag the tab to reorder the comparison. The three-dot menu can rename, clone, disable, recolour, or remove a scenario; a disabled tab keeps its values but is omitted from comparisons.

The Compare checkbox shows every enabled scenario or only the open tab. Three-dot menus beside input-group titles can copy that group from another scenario, keep two groups synchronized, or restore the group defaults. A visible sync mark identifies linked groups and stops synchronization when selected.

Two investment scenarios with numbered markers around the side-by-side comparison, scenario tabs, pin button, and advanced options foldout.
  1. 1
    Side-by-side summary calls out the assumptions that differ.
  2. 2
    Scenario tabs choose which complete set of inputs you are editing; their menus manage names, copies, colours, and comparison participation.
  3. 3
    Compare and Pin switch between one or several enabled scenarios and keep a section at the top while you scroll.
  4. 4
    Advanced options open only when you need finer control.

Pins are available on larger screens where a sticky section can leave enough room for the page below it. They are hidden on phones.

The portfolio tracker uses the same strip for separate portfolios rather than what-if copies. A new Portfolio tab starts empty, while names, colours, ordering and side-by-side totals work like calculator scenarios. Its holding filters also limit the per-holding value, gain, cost, allocation and day-mover views without changing the complete portfolio totals or Asset-type summary.

Explore charts and tables

Select a chart or table heading to collapse or reopen that section. Hover a chart mark—or focus it with Tab—to read its exact value. Legends use the same scenario colours throughout the page.

A two-scenario balance chart with numbered markers around its foldout heading, line display control, export button, and plot.
  1. 1
    Foldout heading closes or opens the chart and remembers the choice.
  2. 2
    Line or column changes the chart shape without changing its data.
  3. 3
    Section export exports this chart rather than the whole page.
  4. 4
    Plot shows every scenario in its chosen colour; inspect marks for exact values.

Wide tables scroll inside their card on a small screen. The page itself should not need to scroll sideways.

Export a page or one section

The top Export menu prepares a report for the entire calculator. Export buttons inside chart and table headings use the same format menu but limit the report to that section.

ExcelWorkbook with structured report tables.
CSVPlain tabular data for another analysis tool.
Markdown or JSONPortable text for notes, code, or automation.
HTML or PDFFormatted reports for reading and sharing.

Export uses the result already displayed. If you change an assumption, wait for the page to refresh before downloading the new report.

What this browser remembers

Your form values, scenarios, portfolio holdings, shares, average costs, saved quotes, scenario or portfolio order and colours, open or closed sections, pins, chart shapes, theme, and tips setting are saved in this browser. They are not a substitute for a report or backup. Use Reset to return the current calculator to its shipped defaults.

Sign in to synchronize appearance across devices without unlocking your vault. Theme, chart colors and styles, tips, sliders, number display, calculator layouts, expanded and pinned sections, and table column settings follow your account. The first browser initializes an empty account appearance profile; afterward, online preferences replace FREE-mode appearance on other devices.

Appearance changes save automatically after five seconds without another change, or within fifteen seconds while you keep editing. Returning to a page refreshes its preferences. Offline edits wait on this device until you reconnect; check the appearance sync message in Settings or Account. If two devices change the same setting, the online value is kept. Browser-close uploads are best effort, so leave the page open until it says Appearance synced before relying on another device.

Saved calculations and session files contain financial inputs and scenarios, while account appearance stays separate. Restoring an older session uses your current appearance. Calculator Reset preserves appearance; use the dedicated layout, table, or Settings reset controls to change those preferences.

For encrypted account saves, Remember me on this device is on by default. Unlock once on your personal browser and you can return after switching pages or restarting it. Lock vault or Sign out forgets the unlock in this browser's tabs. Uncheck remembering on shared devices: you will need to unlock again after leaving the page. Your passphrase is never saved or sent to us. Clearing website data also forgets the unlock; keep your passphrase or recovery key safe.

After you open Account, this browser remembers PRO access and opens the corresponding PRO calculator when you return to a public calculator address. You can still choose an explicit FREE link, and offline calculators remain FREE.

An open PRO calculator stays in PRO mode without periodic access checks, even if your subscription expires while you are using it. Access is checked when you navigate, reload, return through browser history, or view Settings → Account. Hiding a tab or being inactive does not lock your vault. Cloud saves still require an authorized account; a connection failure leaves your open calculation available locally.

Use Share on any calculator except Portfolio to copy a link containing every scenario and its inputs. Anyone with an unprotected link can read its contents. Enable Password-protect to encrypt the link, and send the password separately. The password is never saved; a lost password cannot be recovered.

Sharing links contain their data after the # in the address, so the shared inputs are not sent to the website server. The full address must fit within 4 KB; if you see Link too long, reduce the session or use Save to download its JSON file instead.

Opened links are temporary: editing, switching scenarios, and Reset leave your saved inputs intact. Save locally asks before replacing your saved scenarios. Return to saved session discards temporary changes. Reloading a sharing URL reopens the original shared inputs, and changes are lost unless saved locally or shared through a new link. Sharing uses current Chrome, Safari, or Firefox; password protection requires a secure browser context such as HTTPS.

Keyboard and focus

  • Use Tab and Shift+Tab to move through interactive controls.
  • Use Space or Enter to activate buttons and open foldouts.
  • Use arrow keys on sliders and option groups for small, controlled changes.
  • Focused chart marks show the same exact-value details as pointer hover.

Read projections as scenarios, not promises

The calculators apply the assumptions you provide. Market returns, inflation, taxes, fees, aid, property costs, and future rules can differ from those assumptions. Compare several plausible scenarios and inspect each page's What this assumes section.

Calculations are estimates for planning and education. They are not personalized financial, tax, legal, or investment advice. See the Financial Disclaimer for the full limitations.

Troubleshooting

The answer disappeared
Check the form for a validation message or an out-of-range value. A valid result returns automatically.
A slider will not reach my typed value
The typed number is authoritative. A value outside the slider's convenient range can pin the slider to one end.
I cannot see the pin buttons
Pins are intentionally hidden on narrow screens.
Portfolio search or refresh is unavailable
Marketstack lookup is development-gated until a commercial-use key is configured. Saved, manual and illustrative prices remain available, and a failed lookup or refresh does not erase them. Manual entry checks a recognized exchange by its MIC and keeps the values you entered when no supported quote is returned.
I want to start over
Use Reset on the calculator. For help with the site, visit Contact & Support.