What this site is
- A hub of twelve calculators covering mortgage refinancing, PMI removal, home equity, insurance deductibles, lease vs buy decisions, auto refinancing, and the pay-off-mortgage-vs-invest question.
- Each calculator produces a clear verdict based on the math: ✅ green light, ⚠️ depends, or ❌ don't.
- Every formula is the standard published version — PMT for amortizing loans, future-value for time-of-money comparisons, after-tax math for investment comparisons. Full methodology here.
- Where the math says "don't do this," the calculator says "don't do this" — even when the page's affiliate offer would benefit from the opposite.
What this site isn't
- Financial advice. The calculators are planning tools. The number you get is a directional estimate based on the inputs you provide. Your real-world outcome depends on terms quoted by lenders, your tax situation, market conditions at the time you act, and life events no calculator can anticipate.
- A replacement for a Loan Estimate. When you apply for a mortgage, your lender is required by federal law (TRID, 2015) to provide a Loan Estimate within 3 business days. That document is the official figure — not our calculator. Use our calculator to decide whether to apply; use the Loan Estimate to decide whether to sign.
- A licensed advisor. Our calculators don't know your full financial picture, tax situation, or goals. For complex decisions — especially Roth conversions, retirement timing, or significant cash-out refinancing — consult a fiduciary financial advisor or CPA.
How we think about the math
Three principles shape every calculator on the site:
1. The verdict is the deliverable
Numbers without interpretation are noise. Every calculator on the site ends with a clear verdict in plain language. Sometimes that verdict goes against what looks like the obvious answer — "the bi-weekly mortgage program charges fees that eat the savings, skip it" or "your math says invest, but your behavior says pay the mortgage." When the right answer is "depends," we say "depends" and explain what it depends on.
2. Affiliate offers don't bend the verdict
This site has affiliate relationships with lenders and insurance comparison platforms. We earn a referral fee if you click through and complete a transaction. That financial reality matters and we disclose it on every page.
What we don't do is let the affiliate relationship influence the calculator's output. The math doesn't know our affiliates exist. When the math says "don't refinance," the page says "don't refinance," and the affiliate CTA still sits at the bottom — clearly marked as one option among others, not the recommendation. If you're using our site to figure out what to do, you should get the honest answer.
3. Disclosure beats persuasion
Our calculators explain every assumption upfront: what investment return rate we used, what tax bracket we assumed, what mortgage insurance rules apply to your loan type. Where assumptions matter, we make them user-inputs. Where formulas are non-obvious, the methodology page explains them.
Editorial policy
- Sources cited. Where we cite a regulation (Homeowners Protection Act for PMI, TCJA 2017 for interest-deductibility rules, etc.), we cite the actual law or rule.
- Updated dates visible. Every calculator carries a "Updated" date so you know how recent the rate-environment assumptions are.
- Errors corrected fast. If a calculation is wrong, we fix it and note the correction. Mail: corrections@themathsays.com (placeholder during launch — see contact below).
- No content farm. We're not adding marginally relevant "best of" listicles to chase traffic. Twelve calculators, done well.
About the editorial team
The Math Says is built by a small editorial team with backgrounds in personal finance writing, mortgage lending, and software. We deliberately publish under a team byline rather than an individual one — the calculators are tools, not opinions, and we want them to stand on the math instead of any single contributor's reputation. This is the same model Wirecutter and the early NerdWallet used.
What that means in practice:
- Every calculator on this site is reviewed by at least two team members before publication.
- Every formula is documented in plain language on our methodology page. If we can't show our work, it doesn't ship.
- Every numeric claim (rate ranges, fee averages, regulatory citations) is sourced from public industry data or specific regulations. The methodology page lists the sources.
- When facts change — rates, tax law, MIP rules — we update the affected calculators and stamp the new "Updated" date.
What we don't claim:
- We are not a licensed lender, mortgage broker, insurance agent, financial advisor, or tax preparer in any jurisdiction.
- Our calculators are planning tools, not advice — see the full disclaimer for what that means.
- For high-stakes decisions, consult a licensed professional. We exist to help you decide whether to consult one in the first place.
How to reach us
Corrections, factual disputes, or methodology questions: editorial@themathsays.com. We respond within 7 business days; confirmed errors are corrected within that window with a note on the affected calculator.
Affiliate or partnership inquiries: partners@themathsays.com. We accept partnerships only with companies whose products our calculators would already recommend on the math.