A calculator is only useful if you can trust its numbers. This page explains how we build, check, and update every tool on RateMath.
1. Standard, Published Formulas
Each calculator uses widely accepted financial formulas, such as the compound interest formula for APY and the standard amortization formula for loan payments. Where a U.S. regulation defines how a figure must be calculated (for example, APY under Regulation DD), we follow that definition. We show the formula on every calculator page so you can check the math yourself.
2. Checked Against Independent Calculations
Before a calculator goes live, we test it with multiple sets of inputs and compare the results with independent calculations done separately from the calculator’s code. We also test edge cases, such as a 0% rate or a very long time period, to make sure the tool behaves sensibly.
3. Official U.S. Sources
Facts about rules, limits, and taxes come from primary sources, including:
- Consumer Financial Protection Bureau (CFPB)
- Federal Deposit Insurance Corporation (FDIC)
- National Credit Union Administration (NCUA)
- Board of Governors of the Federal Reserve System
- Internal Revenue Service (IRS)
Each page lists the specific sources it relies on.
4. Clear Assumptions
Every calculator states its assumptions, such as a fixed rate, no fees, or no withdrawals. Real accounts and loans can differ, so results are estimates, not quotes or offers.
5. Regular Updates
We review pages when laws, limits, or tax rules change, and each page shows the date it was last updated.
6. Tools We Use
We use software tools, including AI writing assistants, to help draft and edit explanations. Every formula, example, and figure is checked by a person before it is published.
7. Corrections
If you spot an error, please contact us. We review every report and fix confirmed errors promptly.
8. Independence
Advertisers and partners have no say in how our calculators work or what our explanations say.