How Centave works

This page is our methodology and editorial policy in one place: how calculators are built, how the math is tested, where our figures come from, what the dates on each page mean, and how to get something fixed.

How calculators are built

Every calculator on the site is driven by a configuration that declares its inputs, outputs, and formula — and the formulas themselves live in small, isolated math engines with no knowledge of the page around them. The credit card payoff calculator, for example, uses standard declining-balance amortization: each month, interest accrues on the current balance at one-twelfth of the APR, the payment is applied, and the remainder reduces principal — the same method issuers use on your statement.

Because the math is separated from the presentation, every calculator that shares a concept (like amortization) shares one implementation. A bug fixed in the engine is fixed everywhere at once.

How we test the math

Every engine and every calculator configuration has automated unit tests — worked scenarios with known correct answers that run on every change. Our continuous-integration pipeline blocks any change that breaks a test, and accessibility is checked automatically too (every page template runs through automated axe audits).

We also fail our own build for content quality: if the explainers on two similar calculators become too similar to each other, an automated check stops the site from publishing until they're genuinely different. You should never land on two Centave pages that say the same thing in different order.

Where our figures come from

Market figures — like the average credit card APR — change constantly, so we keep every volatile number in a single cited registry rather than typing it into pages by hand. Each figure carries its source and the date we last confirmed it, and every page that mentions it renders from the registry, so an update in one place corrects the whole site.

Figures currently in the registry:

• Average credit card APR: 24.35% — from the Federal Reserve G.19 Consumer Credit report, confirmed 2026-05-01.
• Average 60-month new auto loan APR: 7.1% — from the Federal Reserve G.19 Consumer Credit report, confirmed 2026-05-01.

We cite primary sources — the Federal Reserve, the Consumer Financial Protection Bureau — not other websites' summaries of them.

What the dates on each page mean

Every calculator and data page shows two dates. Last updatedis when the page's content last changed for any reason. Reviewed is when someone last re-checked the math and every cited figure against its source — a full fact-check pass, not a copy edit. The two are tracked separately on purpose: a page can be freshly worded and still overdue for review, and the dates will tell you that honestly.

Editorial policy

The site is supported by advertising (how we make money), and advertising never changes the math or the guidance. When a page recommends a strategy — like putting extra payments toward the highest-APR balance first — it's because the arithmetic supports it. We update pages when rates move, when regulations change, and when readers report problems.

Our use of AI

We use AI tools to help draft explainers and build the site. Two things are never delegated to AI: the math, which is deterministic, tested code rather than generated text; and publication, which is gated on the human review pass reflected in each page's Reviewed date. If AI helps write a sentence, a person still checks the claim behind it.

Corrections

If a number looks wrong, tell us — include the calculator's address and the inputs you used, via the contact page. We treat corrections as bugs: reproduce, fix, and update the affected page's dates. Meaningful corrections are noted on the page itself.

See also: about Centave and terms of use.