About Coastline
Coastline is a free retirement and FIRE calculator for the US and Canada. It projects a whole financial life year by year — earning, saving, buying a home, paying off debt, retiring, drawing down — with real federal, state and provincial tax math, and it shows the arithmetic behind every single number.
Who builds it
Coastline is built and maintained by an independent developer. It started as a personal tool. I wanted to answer “can I actually afford to do this?” and found that most free calculators either hid their assumptions, ignored taxes entirely, or wanted an account and an email address before showing a single number. So I wrote one that does the tax math properly and shows its work.
An honest statement of credentials
I am a software engineer, not a licensed financial advisor. I am not a CFP, CPA, tax attorney, or registered investment adviser. Nothing on this site is financial, tax, legal, or investment advice, and using it creates no advisory relationship. I do not know your situation, and Coastline cannot know it either — it only knows the inputs you give it.
What I can claim is narrower and, I think, more useful: the calculations are real, they are checked, and they are visible. Coastline implements the actual published tax rules rather than a flat “effective tax rate” guess, and the engine is covered by an automated verification suite that includes dozens of hand-computed assertions and a reconciliation check that every tax column sums to the total tax on every projected row. Where the model simplifies something, the methodology page says so by name rather than quietly rounding it away.
The right way to use Coastline is as a way to see the shape of a decision and pressure-test it — then take the result to a qualified professional before you act on it.
How the projections are produced
Every figure on this site is computed at build time by the same engine the interactive app runs — nothing on these pages is hand-typed or copied from another calculator. When a guide says a portfolio lasts to a particular age, that number came out of a full year-by-year projection with tax, inflation, and withdrawal ordering applied. Full methodology →
How it is funded, and what happens to your data
- Free, with no ads. There is no paid tier, no upsell, no lead-generation form, and no advisor-referral kickback. Nobody pays for placement in the comparison pages — including the pages where I say a competitor is the better tool for a given job.
- No accounts and no database. You never create a login, because there is nothing to log in to.
- Your inputs are not stored. To run the projection your inputs are sent to the server, used to compute the numbers, and then discarded — they are never stored, logged, or tied to you. A copy is kept in your own browser’s local storage so your plan is still there when you come back; clearing your browser data erases it. To move a plan between devices you export a code and paste it back in — that code never touches a database either.
- Anonymous, cookieless usage stats only. They tell me which pages get used. No personal or financial information is ever collected.
Corrections and contact
If a number looks wrong, I want to know — tax rules change every year, and a finance tool that silently drifts out of date is worse than no tool. Corrections, bug reports, and feature requests all go to the same place:
Tax constants are reviewed and updated annually against the primary sources; the methodology page documents that process and lists the sources.
Common questions
Is Coastline free?
Yes — completely. There is no paid tier, no trial, no ads, and no account. You do not need to give an email address to use it.
Is the person behind Coastline a financial advisor?
No. Coastline is built by a software engineer, not a licensed financial advisor, CFP, or CPA. It is an educational modeling tool, not advice, and you should confirm any decision with a qualified professional.
Does Coastline store my financial information?
No. There are no accounts and no database. Your inputs are sent to the server only to run the projection and are then discarded — never stored, logged, or tied to you. A copy stays in your own browser so your plan survives a reload.
How does Coastline make money?
It does not. There are no ads, no affiliate links, no lead-generation forms, and no paid placements in the tool comparisons.
How do I report a wrong number?
Email FinancialDecSim@gmail.com. Tax rules change annually and corrections are genuinely welcome — the constants are reviewed each year against IRS, SSA, and CRA publications.