Editorial policy & methodology

Who is responsible

The Coast FIRE Calculator editorial team maintains the code and explanations for the independent publisher. We check account limits, tax figures and benefit rules against the responsible agency’s official publications, tables and instructions. When a reader reports an issue, we reproduce the example, check the governing source, correct confirmed errors and verify the result. The tools are for education and planning, not personal tax or financial advice.

Define the question before the formula

Each calculator should specify the decision it models, required inputs, units, tax year or jurisdiction, and excluded cases. A retirement projection is an assumption-driven model; a contribution-room calculation is a rule-bound limit; a withholding estimate is not a final tax bill. Combining these as one number would obscure what the result can tell a user. We explain important boundaries near the tool and provide related pages for separate tasks rather than promising a complete personal plan.

Prefer primary sources

For government rules, we prioritize the responsible agency's publications, instructions, tables and official examples. Examples include IRS notices and publications for US accounts and tax, CMS and SSA for Medicare and Social Security, CRA and Service Canada for Canadian accounts and benefits, and OPM for federal pensions. An outside summary may help find a rule but is not the final authority. A linked source alone is not proof that every exception has been implemented: the page must identify its supported scope.

A source-check date means the stated rule or data was checked on that date. It does not mean the government endorses the tool or that every page is updated daily. We retain the relevant year on indexed tables and do not change a date merely because a site was redeployed. We separate annual limits from monthly data, permanent mechanics and example assumptions. We update affected rules and figures when official numbers are published or changed. A page’s stated check date is its last recorded check for that material, not a promise of a scheduled review.

Make arithmetic inspectable

We use worked examples with explicit inputs and explain how those inputs affect the output. For eligible cases, tests cover published examples, thresholds and boundary conditions such as zero values, changes of year or filing status, excluded account types and incomplete data. Interface checks confirm that an edited input changes the visible result and that small-screen tables remain usable. Tests demonstrate the behaviors tested, not that all possible legal or personal cases are covered.

Code provenance

The core FIRE calculation module records adaptation from fireplanner, published under the MIT license. We retain its copyright and permission notice. The source code identifies the adapted module, and the retained license documents its provenance.

Handle uncertainty openly

Growth projections do not predict future returns, inflation, lifespan or spending. Smooth annual growth does not model every market sequence. Tax and benefit tools may omit state rules, credits, deductions, plan provisions or record-specific exceptions. We describe these limits alongside the relevant tool and investigate differences between an official publication and a worked example.

Corrections and maintenance

Use the Contact page to report an error with a page URL, non-sensitive example and source. We aim to reproduce the issue, check the governing rule, update the code or explanation, add a relevant regression test, and verify the deployed result. Include enough detail for us to reproduce the calculation and identify the applicable rule.

Advertising and privacy

The site is intended to be supported by advertising. Advertisers do not determine the calculator result. A code tag or ad placeholder does not establish AdSense approval. We do not encourage visitors to click advertising, delay results to generate views, or require advertising interaction to use a tool. Our Privacy Policy separates local calculation, optional analytics, hosting records and Google's advertising consent controls.