Methodology

How tools are built

Calculators are written in TypeScript as pure functions inside a shared package (@bedrocka-tools/calc), with Vitest unit tests that cover edge cases: zero-interest loans, negative-cash-flow companies, SBA fee bracket boundaries, and every published sample problem we can find from primary sources. The package has no UI and no side effects — if a calculator gives the wrong answer, there's one file to fix and a failing test that tells us it was wrong.

Formula sourcing — primary sources only

We only cite primary sources. Blog-of-a-blog-of-a-PDF is not a source. Primary sources we use routinely on this site:

• IRS Publications (irs.gov) — Pub 560 (Retirement Plans for Small Business), Pub 535 (Business Expenses), Pub 334 (Tax Guide for Small Business), Pub 969 (HSAs), Pub 587 (Home Office), Form 1040-ES instructions
• Internal Revenue Code — IRC §199A (QBI), §401(k), §408(k) (SEP-IRA), §415(c) (contribution limits), §1366 (S-Corp), §3121 (SE tax / FICA), §162(l) (self-employed health insurance), §223 (HSA), §36B (premium tax credit)
• Treasury Regulations — Treas. Reg. §1.199A-1 through -6, §1.401(k)-1 through -6, §1.415(c)-1
• IRS Revenue Procedures — annual cost-of-living adjustment Rev. Procs. for retirement contribution limits and tax bracket thresholds
• HHS and CMS guidance (hhs.gov, healthcare.gov) for ACA marketplace, HDHP definitions, HSA-eligible plan requirements
• State Department of Revenue guidance — cited by state and labeled as state-specific when state conformity diverges from the federal rule

Secondary sources are used only where a primary source does not exist and are always labeled as such.

Review process

1. Draft: calculator logic and explanatory copy are drafted, sometimes AI-assisted, always with the primary source pulled up in parallel and every non-trivial number checked against it.
2. SME review: each calculator is reviewed by a named human with operator experience in the domain — for finance calculators, Byron Malone in his operator capacity, and for new tools outside that expertise we engage domain reviewers and credit them on the page.
3. Citation verification: every URL cited is spot-checked at publish time and every named rule or rate is re-checked against the source document.
4. Publish: with a Last updated stamp and a dateModified schema.org field on every page.

Update cadence

Every calculator is reviewed on a quarterly cadence. In addition, we update immediately on any of the following triggers:

• IRS publishes annual cost-of-living adjustment Rev. Proc. (retirement contribution limits, QBI thresholds, SE tax wage base)
• IRS issues a new Publication revision affecting any category on this site
• Congress passes legislation that changes SE tax, QBI, or retirement plan rules
• Treasury issues final or proposed regulations affecting IRC §199A, §401(k), §408(k), or §415(c)
• HHS or CMS issues updated HDHP/HSA limits or ACA marketplace guidance

Error reporting

If a calculator gives you the wrong answer, we want to hear. Email info@bedrockatools.com with the tool, the inputs you used, and the output you got. We respond to every report within 3 business days; if the tool is wrong, we fix it and publish a correction note on our corrections page.

Per-category methodology

Each calculator category has a dedicated methodology page covering the primary sources, formula derivations, edge cases, and update protocol specific to that category. Calculators marked as launching soon are stubs in active development; the methodology pages are live so readers can evaluate the sourcing before the calculator ships.

• Retirement Savings — Solo 401(k) vs SEP-IRA contribution comparator. Primary sources: IRC §401(k), §408(k), §415(c), IRS Pub 560.
• Entity Structure — LLC vs S-Corp self-employment tax decision. Primary sources: IRC §1366, §3121, IRS Form 2553 instructions.
• Tax Deductions — QBI deduction calculator. Primary sources: IRC §199A, Treas. Reg. §1.199A-1 through -6, IRS Pub 535.
• Health Coverage — self-employed health insurance deduction, HSA eligibility, ACA marketplace. Primary sources: IRC §162(l), §223, §36B, HHS/CMS guidance. Note: computational calculator for this category launches after credentialed reviewer sign-off per our editorial standards.
• Operating Finance — freelancer cash flow, project pricing, quarterly estimated tax. Primary sources: IRS Form 1040-ES, IRS Pub 334, IRS Pub 535.

Limitations

Calculators on this site are estimatesfor educational use. They do not account for every state's conformity to federal tax law, every individual income scenario, every plan-specific rule a custodian or employer plan might apply, or the specifics of your individual filing situation. They are not tax, financial, investment, or legal advice. Consult a licensed CPA, Enrolled Agent, or tax attorney for decisions with real dollars and real tax liability attached. The tools are designed to make you a better-informed buyer of professional advice, not a replacement for it.