Editorial Guidelines

Accuracy comes first

A calculator is only useful if its numbers are right. Before a calculator is published, we:

• Implement the standard formula for the product, such as the amortization formula for fixed-rate loans or the compound growth formula for savings, using exact decimal arithmetic.
• Write automated tests with expected values derived independently, by a separate implementation and from published reference figures, never by the code being tested.
• Test the edge cases that trip calculators up: zero interest rates, payments larger than the balance, balances that never pay off, and rounding at the final payment.
• Generate every number in the article from the same code that powers the calculator, so examples and results always match.

Our methodology page describes the testing process in detail, along with where our data comes from and when each source is updated.

Transparent assumptions

Every calculator states its assumptions on the page: how often interest compounds, when deposits are made, how rounding works and which simplifications we make (for example, treating a credit card minimum payment as a fixed amount). Where real products can differ from our model, we say so and explain the direction of the difference.

Sources we rely on

We base rules and definitions on primary sources: federal agencies such as the Consumer Financial Protection Bureau, the FDIC, the NCUA, the IRS and the Federal Reserve, and the text of federal statutes. Each article lists its sources. We avoid quoting market rates that go stale quickly; where an example uses a rate, it is illustrative and labeled as such.

Plain language

We write for people making real decisions, not for specialists. Terms such as APR, APY, PMI and amortization are defined where they first appear, and every formula comes with a worked example in dollars.

Independence from advertising

The site is funded by advertising. Ads are labeled and placed in reserved spaces separate from calculator results and article text. Advertisers cannot request changes to formulas, defaults, examples or recommendations, and we don't publish sponsored calculators or paid placements in our articles.

Reviews and updates

Each calculator page shows the date it was last updated. We review pages when the rules they describe change, for example deposit insurance limits or federal rules on mortgage insurance, and whenever a reader reports a possible problem.

Corrections

If you believe a result, formula or statement is wrong, tell us. Please include the page, the inputs you used and the result you expected. We investigate every report, fix confirmed errors promptly, and update the page's date when a correction changes what it says.

Not financial advice

Our content is educational. It explains how financial products work and how to compare them, but it can't account for your full circumstances. For decisions with significant consequences, confirm details with your lender or bank and consider consulting a qualified financial, tax or legal professional.