About KalkWise
Free financial calculators,
built for accuracy
KalkWise provides free, independent financial calculators for everyday money decisions — compound interest, mortgages, retirement, loans, debt payoff, and more. Every calculator is free to use, requires no login, and is funded by display advertising.
Our mission
Good financial decisions start with accurate numbers. Too many free calculator sites show oversimplified results, bury the math, or are lead-generation funnels for financial products. KalkWise is different: every calculator shows the formula behind the result, the assumptions it makes, and its known limitations — so you can trust the output and understand what it means for your situation.
Editorial team
KalkWise Editorial Team
Financial Research & Calculator Methodology
Our editorial team researches, writes, and verifies every calculator on KalkWise. Formulas are cross-checked against authoritative sources including IRS publications, Freddie Mac data, and standard actuarial tables. Content is reviewed for accuracy before publication and updated whenever regulations or standard rates change.
Our methodology
Formula accuracy. Every calculation is implemented against standard financial mathematics formulas and cross-verified against multiple authoritative sources before publication. For loan calculations we use the standard amortization formula. For retirement projections we use compound growth simulation run month-by-month for precision (not the simplified annual approximation many sites use).
Conservative defaults. Where we must choose a default input value we choose conservatively — for example, we use 7% as a default long-term stock market return (below the historical S&P 500 average of ~10%) to avoid overly optimistic projections.
Transparent assumptions. Every calculator page includes a "Limitations" section that explicitly states what the calculator does not model — tax impacts, variable rates, inflation adjustments, and so on.
Regular updates. Tax brackets, contribution limits, and standard rates change annually. We review and update affected calculators after each IRS announcement and Federal Reserve cycle. Content on this site was last reviewed in June 2026.
Data sources
| Calculator area | Primary source |
|---|---|
| Mortgage rates & amortization | Freddie Mac Primary Mortgage Market Survey (PMMS) |
| Federal income tax brackets | IRS Publication 15-T, Revenue Procedure 2023-34 |
| 401k contribution limits | IRS Notice 2023-75 |
| Inflation / CPI data | U.S. Bureau of Labor Statistics (BLS) |
| Social Security COLA | Social Security Administration (SSA) |
| Standard amortization formula | Actuarial Society of America / standard financial mathematics |
| FIRE / 4% rule | Trinity Study (Cooley, Hubbard, Walz — updated 2011) |
Disclaimer
KalkWise calculators are provided for general informational and educational purposes only and do not constitute financial, investment, tax, or legal advice. Results are estimates based on the figures you enter and the assumptions stated on each calculator page. Actual outcomes will vary. Consult a qualified professional — such as a Certified Financial Planner (CFP®), CPA, or licensed attorney — before making significant financial decisions.
Advertising & independence
KalkWise is free and funded by display advertising through Google AdSense. We do not accept sponsored calculator results, paid placements, or affiliate commissions that influence calculator outputs. Ads are served by Google and are clearly marked. Our calculator results are never influenced by advertisers.
Contact
Found an error in a calculation? Have a suggestion for a new calculator? We welcome feedback.
Email: hello@kalkwise.com