About PayoffCalcs

Who made this

I am an independent developer who builds financial calculation tools. I do not have a CFA or CPA, and I am not a licensed financial advisor. I am honest about that because you should know who is giving you numbers that affect your money.

Calculator formulas are documented and tested against independently calculated reference cases. Where a calculator uses current rates, tax figures, or lending thresholds, the relevant source and update date are provided. Real lender results may differ because of fees, rounding, daily-interest methods, and institution-specific rules.

I built PayoffCalcs because I was tired of finance sites that buried calculators under pop-ups, demanded emails before showing results, or wrapped generic advice in guru language. The math behind lending and investing is not secret — much of it uses standard amortization and compound-growth formulas. The calculators run those formulas in your browser. Shareable inputs are kept in the URL fragment, which is not included in normal requests to the site.

I do not sell investment products. I do not take referral fees from lenders. I do not have a course to push. This is a solo project built because the existing options frustrated me, and I think you deserve better than dark patterns.

Editorial standards

1. Prefer primary sources. Government and regulator sources are used whenever available. Reputable research is identified clearly when primary government data is unavailable.
2. Document assumptions. Each calculator explains its formulas, inputs, assumptions, and important limitations.
3. Correct material errors. Significant corrections are dated and disclosed on the affected page.

What this is

PayoffCalcs is a set of 15 browser-based calculators for debt, borrowing, saving, and long-term planning. You enter values and get an estimate immediately. The tools cover mortgages, auto and student loans, credit-card payoff, snowball and avalanche ordering, home affordability, DTI, emergency funds, savings goals, compound growth, retirement projections, budgeting, and net worth.

Alongside the calculators, I write plain-language guides that explain the math behind each decision. They include formulas, worked examples, and source links where outside data is used. The goal is to help you understand an estimate and ask better questions before making a decision decisions and have productive conversations with professionals when you need them.

How the math works

Nothing fancy here — just standard amortization math. The same formulas banks use, minus the sales pitch. Every calculator on this site is documented on our Methodology page with the exact formula, variable definitions, worked examples, and primary data sources. Here are the core ones:

• Amortization: M = P × [r(1+r)ⁿ] / [(1+r)ⁿ – 1] — the standard loan payment formula used by most US lenders.
• Compound interest: FV = P(1 + r/n)^(nt) — how investments grow when interest earns interest.
• Debt-to-income: DTI = (Monthly Debt Payments ÷ Gross Monthly Income) × 100 — the metric lenders use to decide approval.
• Debt payoff orderings: Avalanche prioritizes the highest APR to reduce interest; snowball prioritizes the smallest balance to create earlier milestones.
• Retirement: Future value of savings + contributions, then the 4% rule as a historical withdrawal guideline.

Rate benchmarks, tax brackets, and thresholds are sourced directly from the Federal Reserve, CFPB, IRS, and Freddie Mac. Rate and tax data is refreshed on the schedule documented on our Sources page.

Why it is free

PayoffCalcs may use limited advertising in the future to cover hosting and maintenance costs. There are no pop-ups, no forced sign-ups, no premium tiers. The ads sit to the side or between sections — they do not interrupt your calculation. If the ad situation ever changes, I will update this page. I am not interested in turning this into a lead-gen funnel.

The static, client-side setup keeps hosting costs low. I intend to keep the calculators free; if advertising is introduced, this page and the privacy policy will explain how it is used.

Privacy

• Calculator values stay in browser-controlled state. Loan amounts, rates, and payment details are processed locally. Shareable values appear after the # in the address bar, which browsers do not send in normal page requests.
• Limited tracking. The site itself sets no tracking cookies. If advertising is enabled in the future, ad networks (like Google AdSense) may set cookies to serve and personalize ads.
• No personal info asked for. No names, no emails, no phone numbers. Nothing that could identify you.
• HTTPS only. The entire site runs on HTTPS. No mixed content, no insecure requests.

Full details in the Privacy Policy.

What this is not

• Not financial advice. Calculators give estimates based on your inputs. They do not know your full financial situation, tax status, or goals.
• Not a substitute for a professional. For major decisions (buying a home, retirement planning, debt strategy), talk to a licensed advisor who can see your whole picture.
• Not affiliated with any bank, lender, or government agency. PayoffCalcs is independent. We do not accept compensation from any financial institution.

See the Disclaimer for the full legal framing.

Contact

Questions, bug reports, or suggestions? Email me directly at payoffcalcs@gmail.com. I try to respond within a day or two. If it is a bug, include which calculator you were using and what numbers you put in — it saves a lot of guesswork. If it is a calculator idea, tell me what tool you wish existed and I will consider building it.