People use our calculators to make real decisions about money, health, school, and home projects, so accuracy matters. This page explains exactly how each tool is built and reviewed, where our numbers come from, and how we correct mistakes. We'd rather over-explain our process than ask you to take a result on faith.
Who produces our calculators
Every calculator is built and reviewed by The Calcery Editorial Team — the small group that designs, codes, and checks each tool and its accompanying explainer. Calculators are not auto-generated and published untouched: each one is implemented deliberately, tested against known results, and paired with a written explanation, a worked example, and answers to common questions before it goes live.
How we choose our formulas
We use the standard, widely accepted formula for each calculation — for example, the fixed-rate amortization formula for loan payments, the Mifflin–St Jeor equation for resting metabolic rate, or the standard body-mass-index formula. Where an official body publishes the method (such as the IRS for tax figures or the CDC for health thresholds), we follow that method and cite it. When more than one accepted approach exists, we pick a common, defensible one and say so in the calculator's "How we calculate this" note.
How we test accuracy
Before a calculator is published, we check its output against independently worked examples and, where available, against figures from authoritative sources. Calculations run entirely in your browser, so the same inputs always produce the same, reproducible result. If you can reproduce a result by hand or against an official source, you should get the same number we do.
Sourcing and references
On finance, tax, and health calculators we link to primary, authoritative references — for example the Consumer Financial Protection Bureau (CFPB), the IRS, and the CDC. These references appear in the "Sources" section of the relevant calculators so you can verify the basis for a result yourself.
Reviews and updates
Each calculator shows a "Last updated" date reflecting our most recent review of that tool and its content. We revisit calculators when the underlying rates, rules, or recommendations change (for instance, annual tax figures) and when we improve an explanation. Rates and thresholds that change over time are noted as estimates, and we encourage you to confirm time-sensitive figures against the current official source.
Corrections
If you find a result that looks wrong, we want to know. Email us at thecalcery@attainbrands.com or use our contact page with the calculator name and the inputs you used. We investigate reported errors promptly and update the tool and its "Last updated" date when we make a correction.
Independence and advertising
Our calculations and explanations are not influenced by advertisers. The site is supported by advertising, but ads never change a formula, a recommendation, or the content of an explainer. How advertising and cookies work is described in our Privacy Policy.
Limitations and disclaimer
Our calculators provide estimates for general information only. They are not financial, medical, legal, or tax advice, and they cannot account for every individual circumstance. For decisions that matter, please consult a qualified professional. See our About page for more on who we are and why we build these tools.